/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "CacheLog.h"
#include "CacheFileIOManager.h"

#include "../cache/nsCacheUtils.h"
#include "CacheHashUtils.h"
#include "CacheStorageService.h"
#include "CacheIndex.h"
#include "CacheFileUtils.h"
#include "nsThreadUtils.h"
#include "CacheFile.h"
#include "CacheObserver.h"
#include "nsIFile.h"
#include "CacheFileContextEvictor.h"
#include "nsITimer.h"
#include "nsISimpleEnumerator.h"
#include "nsIDirectoryEnumerator.h"
#include "nsIObserverService.h"
#include "nsICacheStorageVisitor.h"
#include "nsISizeOf.h"
#include "mozilla/DebugOnly.h"
#include "mozilla/Services.h"
#include "nsDirectoryServiceUtils.h"
#include "nsAppDirectoryServiceDefs.h"
#include "private/pprio.h"
#include "mozilla/Preferences.h"
#include "nsNetUtil.h"

// include files for ftruncate (or equivalent)
#if defined(XP_UNIX)
#include <unistd.h>
#elif defined(XP_WIN)
#include <windows.h>
#undef CreateFile
#undef CREATE_NEW
#else
// XXX add necessary include file for ftruncate (or equivalent)
#endif


namespace mozilla {
namespace net {

#define kOpenHandlesLimit        128
#define kMetadataWriteDelay      5000
#define kRemoveTrashStartDelay   60000 // in milliseconds
#define kSmartSizeUpdateInterval 60000 // in milliseconds

const uint32_t kMaxCacheSizeKB = 350*1024; // 350 MB

bool
CacheFileHandle::DispatchRelease()
{
  if (CacheFileIOManager::IsOnIOThreadOrCeased()) {
    return false;
  }

  nsCOMPtr<nsIEventTarget> ioTarget = CacheFileIOManager::IOTarget();
  if (!ioTarget) {
    return false;
  }

  nsresult rv =
    ioTarget->Dispatch(NewNonOwningRunnableMethod(this,
						  &CacheFileHandle::Release),
		       nsIEventTarget::DISPATCH_NORMAL);
  if (NS_FAILED(rv)) {
    return false;
  }

  return true;
}

NS_IMPL_ADDREF(CacheFileHandle)
NS_IMETHODIMP_(MozExternalRefCountType)
CacheFileHandle::Release()
{
  nsrefcnt count = mRefCnt - 1;
  if (DispatchRelease()) {
    // Redispatched to the IO thread.
    return count;
  }

  MOZ_ASSERT(CacheFileIOManager::IsOnIOThreadOrCeased());

  LOG(("CacheFileHandle::Release() [this=%p, refcnt=%d]", this, mRefCnt.get()));
  NS_PRECONDITION(0 != mRefCnt, "dup release");
  count = --mRefCnt;
  NS_LOG_RELEASE(this, count, "CacheFileHandle");

  if (0 == count) {
    mRefCnt = 1;
    delete (this);
    return 0;
  }

  return count;
}

NS_INTERFACE_MAP_BEGIN(CacheFileHandle)
  NS_INTERFACE_MAP_ENTRY(nsISupports)
NS_INTERFACE_MAP_END_THREADSAFE

CacheFileHandle::CacheFileHandle(const SHA1Sum::Hash *aHash, bool aPriority, PinningStatus aPinning)
  : mHash(aHash)
  , mIsDoomed(false)
  , mClosed(false)
  , mPriority(aPriority)
  , mSpecialFile(false)
  , mInvalid(false)
  , mFileExists(false)
  , mDoomWhenFoundPinned(false)
  , mDoomWhenFoundNonPinned(false)
  , mKilled(false)
  , mPinning(aPinning)
  , mFileSize(-1)
  , mFD(nullptr)
{
  // If we initialize mDoomed in the initialization list, that initialization is
  // not guaranteeded to be atomic.  Whereas this assignment here is guaranteed
  // to be atomic.  TSan will see this (atomic) assignment and be satisfied
  // that cross-thread accesses to mIsDoomed are properly synchronized.
  mIsDoomed = false;
  LOG(("CacheFileHandle::CacheFileHandle() [this=%p, hash=%08x%08x%08x%08x%08x]"
       , this, LOGSHA1(aHash)));
}

CacheFileHandle::CacheFileHandle(const nsACString &aKey, bool aPriority, PinningStatus aPinning)
  : mHash(nullptr)
  , mIsDoomed(false)
  , mClosed(false)
  , mPriority(aPriority)
  , mSpecialFile(true)
  , mInvalid(false)
  , mFileExists(false)
  , mDoomWhenFoundPinned(false)
  , mDoomWhenFoundNonPinned(false)
  , mKilled(false)
  , mPinning(aPinning)
  , mFileSize(-1)
  , mFD(nullptr)
  , mKey(aKey)
{
  // See comment above about the initialization of mIsDoomed.
  mIsDoomed = false;
  LOG(("CacheFileHandle::CacheFileHandle() [this=%p, key=%s]", this,
       PromiseFlatCString(aKey).get()));
}

CacheFileHandle::~CacheFileHandle()
{
  LOG(("CacheFileHandle::~CacheFileHandle() [this=%p]", this));

  MOZ_ASSERT(CacheFileIOManager::IsOnIOThreadOrCeased());

  RefPtr<CacheFileIOManager> ioMan = CacheFileIOManager::gInstance;
  if (!IsClosed() && ioMan) {
    ioMan->CloseHandleInternal(this);
  }
}

void
CacheFileHandle::Log()
{
  nsAutoCString leafName;
  if (mFile) {
    mFile->GetNativeLeafName(leafName);
  }

  if (mSpecialFile) {
    LOG(("CacheFileHandle::Log() - special file [this=%p, "
         "isDoomed=%d, priority=%d, closed=%d, invalid=%d, "
         "pinning=%d, fileExists=%d, fileSize=%lld, leafName=%s, key=%s]",
         this,
         bool(mIsDoomed), bool(mPriority), bool(mClosed), bool(mInvalid),
         mPinning, bool(mFileExists), mFileSize, leafName.get(), mKey.get()));
  } else {
    LOG(("CacheFileHandle::Log() - entry file [this=%p, hash=%08x%08x%08x%08x%08x, "
         "isDoomed=%d, priority=%d, closed=%d, invalid=%d, "
         "pinning=%d, fileExists=%d, fileSize=%lld, leafName=%s, key=%s]",
         this, LOGSHA1(mHash),
         bool(mIsDoomed), bool(mPriority), bool(mClosed), bool(mInvalid),
         mPinning, bool(mFileExists), mFileSize, leafName.get(), mKey.get()));
  }
}

uint32_t
CacheFileHandle::FileSizeInK() const
{
  MOZ_ASSERT(mFileSize != -1);
  uint64_t size64 = mFileSize;

  size64 += 0x3FF;
  size64 >>= 10;

  uint32_t size;
  if (size64 >> 32) {
    NS_WARNING("CacheFileHandle::FileSizeInK() - FileSize is too large, "
               "truncating to PR_UINT32_MAX");
    size = PR_UINT32_MAX;
  } else {
    size = static_cast<uint32_t>(size64);
  }

  return size;
}

bool
CacheFileHandle::SetPinned(bool aPinned)
{
  LOG(("CacheFileHandle::SetPinned [this=%p, pinned=%d]", this, aPinned));

  MOZ_ASSERT(CacheFileIOManager::IsOnIOThreadOrCeased());

  mPinning = aPinned
    ? PinningStatus::PINNED
    : PinningStatus::NON_PINNED;

  if ((MOZ_UNLIKELY(mDoomWhenFoundPinned) && aPinned) ||
      (MOZ_UNLIKELY(mDoomWhenFoundNonPinned) && !aPinned)) {

    LOG(("  dooming, when: pinned=%d, non-pinned=%d, found: pinned=%d",
      bool(mDoomWhenFoundPinned), bool(mDoomWhenFoundNonPinned), aPinned));

    mDoomWhenFoundPinned = false;
    mDoomWhenFoundNonPinned = false;

    return false;
  }

  return true;
}

// Memory reporting

size_t
CacheFileHandle::SizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const
{
  size_t n = 0;
  nsCOMPtr<nsISizeOf> sizeOf;

  sizeOf = do_QueryInterface(mFile);
  if (sizeOf) {
    n += sizeOf->SizeOfIncludingThis(mallocSizeOf);
  }

  n += mallocSizeOf(mFD);
  n += mKey.SizeOfExcludingThisIfUnshared(mallocSizeOf);
  return n;
}

size_t
CacheFileHandle::SizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf) const
{
  return mallocSizeOf(this) + SizeOfExcludingThis(mallocSizeOf);
}

/******************************************************************************
 *  CacheFileHandles::HandleHashKey
 *****************************************************************************/

void
CacheFileHandles::HandleHashKey::AddHandle(CacheFileHandle* aHandle)
{
  MOZ_ASSERT(CacheFileIOManager::IsOnIOThreadOrCeased());

  mHandles.InsertElementAt(0, aHandle);
}

void
CacheFileHandles::HandleHashKey::RemoveHandle(CacheFileHandle* aHandle)
{
  MOZ_ASSERT(CacheFileIOManager::IsOnIOThreadOrCeased());

  DebugOnly<bool> found;
  found = mHandles.RemoveElement(aHandle);
  MOZ_ASSERT(found);
}

already_AddRefed<CacheFileHandle>
CacheFileHandles::HandleHashKey::GetNewestHandle()
{
  MOZ_ASSERT(CacheFileIOManager::IsOnIOThreadOrCeased());

  RefPtr<CacheFileHandle> handle;
  if (mHandles.Length()) {
    handle = mHandles[0];
  }

  return handle.forget();
}

void
CacheFileHandles::HandleHashKey::GetHandles(nsTArray<RefPtr<CacheFileHandle> > &aResult)
{
  MOZ_ASSERT(CacheFileIOManager::IsOnIOThreadOrCeased());

  for (uint32_t i = 0; i < mHandles.Length(); ++i) {
    CacheFileHandle* handle = mHandles[i];
    aResult.AppendElement(handle);
  }
}

#ifdef DEBUG

void
CacheFileHandles::HandleHashKey::AssertHandlesState()
{
  for (uint32_t i = 0; i < mHandles.Length(); ++i) {
    CacheFileHandle* handle = mHandles[i];
    MOZ_ASSERT(handle->IsDoomed());
  }
}

#endif

size_t
CacheFileHandles::HandleHashKey::SizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const
{
  MOZ_ASSERT(CacheFileIOManager::IsOnIOThread());

  size_t n = 0;
  n += mallocSizeOf(mHash.get());
  for (uint32_t i = 0; i < mHandles.Length(); ++i) {
    n += mHandles[i]->SizeOfIncludingThis(mallocSizeOf);
  }

  return n;
}

/******************************************************************************
 *  CacheFileHandles
 *****************************************************************************/

CacheFileHandles::CacheFileHandles()
{
  LOG(("CacheFileHandles::CacheFileHandles() [this=%p]", this));
  MOZ_COUNT_CTOR(CacheFileHandles);
}

CacheFileHandles::~CacheFileHandles()
{
  LOG(("CacheFileHandles::~CacheFileHandles() [this=%p]", this));
  MOZ_COUNT_DTOR(CacheFileHandles);
}

nsresult
CacheFileHandles::GetHandle(const SHA1Sum::Hash *aHash,
                            CacheFileHandle **_retval)
{
  MOZ_ASSERT(CacheFileIOManager::IsOnIOThreadOrCeased());
  MOZ_ASSERT(aHash);

#ifdef DEBUG_HANDLES
  LOG(("CacheFileHandles::GetHandle() [hash=%08x%08x%08x%08x%08x]",
       LOGSHA1(aHash)));
#endif

  // find hash entry for key
  HandleHashKey *entry = mTable.GetEntry(*aHash);
  if (!entry) {
    LOG(("CacheFileHandles::GetHandle() hash=%08x%08x%08x%08x%08x "
         "no handle entries found", LOGSHA1(aHash)));
    return NS_ERROR_NOT_AVAILABLE;
  }

#ifdef DEBUG_HANDLES
  Log(entry);
#endif

  // Check if the entry is doomed
  RefPtr<CacheFileHandle> handle = entry->GetNewestHandle();
  if (!handle) {
    LOG(("CacheFileHandles::GetHandle() hash=%08x%08x%08x%08x%08x "
         "no handle found %p, entry %p", LOGSHA1(aHash), handle.get(), entry));
    return NS_ERROR_NOT_AVAILABLE;
  }

  if (handle->IsDoomed()) {
    LOG(("CacheFileHandles::GetHandle() hash=%08x%08x%08x%08x%08x "
         "found doomed handle %p, entry %p", LOGSHA1(aHash), handle.get(), entry));
    return NS_ERROR_NOT_AVAILABLE;
  }

  LOG(("CacheFileHandles::GetHandle() hash=%08x%08x%08x%08x%08x "
       "found handle %p, entry %p", LOGSHA1(aHash), handle.get(), entry));

  handle.forget(_retval);
  return NS_OK;
}


nsresult
CacheFileHandles::NewHandle(const SHA1Sum::Hash *aHash,
                            bool aPriority, CacheFileHandle::PinningStatus aPinning,
                            CacheFileHandle **_retval)
{
  MOZ_ASSERT(CacheFileIOManager::IsOnIOThreadOrCeased());
  MOZ_ASSERT(aHash);

#ifdef DEBUG_HANDLES
  LOG(("CacheFileHandles::NewHandle() [hash=%08x%08x%08x%08x%08x]", LOGSHA1(aHash)));
#endif

  // find hash entry for key
  HandleHashKey *entry = mTable.PutEntry(*aHash);

#ifdef DEBUG_HANDLES
  Log(entry);
#endif

#ifdef DEBUG
  entry->AssertHandlesState();
#endif

  RefPtr<CacheFileHandle> handle = new CacheFileHandle(entry->Hash(), aPriority, aPinning);
  entry->AddHandle(handle);

  LOG(("CacheFileHandles::NewHandle() hash=%08x%08x%08x%08x%08x "
       "created new handle %p, entry=%p", LOGSHA1(aHash), handle.get(), entry));

  handle.forget(_retval);
  return NS_OK;
}

void
CacheFileHandles::RemoveHandle(CacheFileHandle *aHandle)
{
  MOZ_ASSERT(CacheFileIOManager::IsOnIOThreadOrCeased());
  MOZ_ASSERT(aHandle);

  if (!aHandle) {
    return;
  }

#ifdef DEBUG_HANDLES
  LOG(("CacheFileHandles::RemoveHandle() [handle=%p, hash=%08x%08x%08x%08x%08x]"
       , aHandle, LOGSHA1(aHandle->Hash())));
#endif

  // find hash entry for key
  HandleHashKey *entry = mTable.GetEntry(*aHandle->Hash());
  if (!entry) {
    MOZ_ASSERT(CacheFileIOManager::IsShutdown(),
      "Should find entry when removing a handle before shutdown");

    LOG(("CacheFileHandles::RemoveHandle() hash=%08x%08x%08x%08x%08x "
         "no entries found", LOGSHA1(aHandle->Hash())));
    return;
  }

#ifdef DEBUG_HANDLES
  Log(entry);
#endif

  LOG(("CacheFileHandles::RemoveHandle() hash=%08x%08x%08x%08x%08x "
       "removing handle %p", LOGSHA1(entry->Hash()), aHandle));
  entry->RemoveHandle(aHandle);

  if (entry->IsEmpty()) {
    LOG(("CacheFileHandles::RemoveHandle() hash=%08x%08x%08x%08x%08x "
         "list is empty, removing entry %p", LOGSHA1(entry->Hash()), entry));
    mTable.RemoveEntry(*entry->Hash());
  }
}

void
CacheFileHandles::GetAllHandles(nsTArray<RefPtr<CacheFileHandle> > *_retval)
{
  MOZ_ASSERT(CacheFileIOManager::IsOnIOThreadOrCeased());
  for (auto iter = mTable.Iter(); !iter.Done(); iter.Next()) {
    iter.Get()->GetHandles(*_retval);
  }
}

void
CacheFileHandles::GetActiveHandles(
  nsTArray<RefPtr<CacheFileHandle> > *_retval)
{
  MOZ_ASSERT(CacheFileIOManager::IsOnIOThreadOrCeased());
  for (auto iter = mTable.Iter(); !iter.Done(); iter.Next()) {
    RefPtr<CacheFileHandle> handle = iter.Get()->GetNewestHandle();
    MOZ_ASSERT(handle);

    if (!handle->IsDoomed()) {
      _retval->AppendElement(handle);
    }
  }
}

void
CacheFileHandles::ClearAll()
{
  MOZ_ASSERT(CacheFileIOManager::IsOnIOThreadOrCeased());
  mTable.Clear();
}

uint32_t
CacheFileHandles::HandleCount()
{
  return mTable.Count();
}

#ifdef DEBUG_HANDLES
void
CacheFileHandles::Log(CacheFileHandlesEntry *entry)
{
  LOG(("CacheFileHandles::Log() BEGIN [entry=%p]", entry));

  nsTArray<RefPtr<CacheFileHandle> > array;
  aEntry->GetHandles(array);

  for (uint32_t i = 0; i < array.Length(); ++i) {
    CacheFileHandle *handle = array[i];
    handle->Log();
  }

  LOG(("CacheFileHandles::Log() END [entry=%p]", entry));
}
#endif

// Memory reporting

size_t
CacheFileHandles::SizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const
{
  MOZ_ASSERT(CacheFileIOManager::IsOnIOThread());

  return mTable.SizeOfExcludingThis(mallocSizeOf);
}

// Events

class ShutdownEvent : public Runnable {
public:
  ShutdownEvent()
    : mMonitor("ShutdownEvent.mMonitor")
    , mNotified(false)
  {
    MOZ_COUNT_CTOR(ShutdownEvent);
  }

protected:
  ~ShutdownEvent()
  {
    MOZ_COUNT_DTOR(ShutdownEvent);
  }

public:
  NS_IMETHOD Run() override
  {
    MonitorAutoLock mon(mMonitor);

    CacheFileIOManager::gInstance->ShutdownInternal();

    mNotified = true;
    mon.Notify();

    return NS_OK;
  }

  void PostAndWait()
  {
    MonitorAutoLock mon(mMonitor);

    DebugOnly<nsresult> rv;
    rv = CacheFileIOManager::gInstance->mIOThread->Dispatch(
      this, CacheIOThread::WRITE); // When writes and closing of handles is done
    MOZ_ASSERT(NS_SUCCEEDED(rv));

    PRIntervalTime const waitTime = PR_MillisecondsToInterval(1000);
    while (!mNotified) {
      mon.Wait(waitTime);
      if (!mNotified) {
        // If there is any IO blocking on the IO thread, this will
        // try to cancel it.  Returns no later than after two seconds.
        MonitorAutoUnlock unmon(mMonitor); // Prevent delays
        CacheFileIOManager::gInstance->mIOThread->CancelBlockingIO();
      }
    }
  }

protected:
  mozilla::Monitor mMonitor;
  bool             mNotified;
};

class OpenFileEvent : public Runnable {
public:
  OpenFileEvent(const nsACString &aKey, uint32_t aFlags,
                CacheFileIOListener *aCallback)
    : mFlags(aFlags)
    , mCallback(aCallback)
    , mKey(aKey)
  {
    MOZ_COUNT_CTOR(OpenFileEvent);
    mIOMan = CacheFileIOManager::gInstance;
  }

protected:
  ~OpenFileEvent()
  {
    MOZ_COUNT_DTOR(OpenFileEvent);
  }

public:
  NS_IMETHOD Run() override
  {
    nsresult rv = NS_OK;

    if (!(mFlags & CacheFileIOManager::SPECIAL_FILE)) {
      SHA1Sum sum;
      sum.update(mKey.BeginReading(), mKey.Length());
      sum.finish(mHash);
    }

    if (!mIOMan) {
      rv = NS_ERROR_NOT_INITIALIZED;
    } else {
      if (mFlags & CacheFileIOManager::SPECIAL_FILE) {
        rv = mIOMan->OpenSpecialFileInternal(mKey, mFlags,
                                             getter_AddRefs(mHandle));
      } else {
        rv = mIOMan->OpenFileInternal(&mHash, mKey, mFlags,
                                      getter_AddRefs(mHandle));
      }
      mIOMan = nullptr;
      if (mHandle) {
        if (mHandle->Key().IsEmpty()) {
          mHandle->Key() = mKey;
        }
      }
    }

    mCallback->OnFileOpened(mHandle, rv);
    return NS_OK;
  }

protected:
  SHA1Sum::Hash                 mHash;
  uint32_t                      mFlags;
  nsCOMPtr<CacheFileIOListener> mCallback;
  RefPtr<CacheFileIOManager>    mIOMan;
  RefPtr<CacheFileHandle>       mHandle;
  nsCString                     mKey;
};

class ReadEvent : public Runnable {
public:
  ReadEvent(CacheFileHandle *aHandle, int64_t aOffset, char *aBuf,
            int32_t aCount, CacheFileIOListener *aCallback)
    : mHandle(aHandle)
    , mOffset(aOffset)
    , mBuf(aBuf)
    , mCount(aCount)
    , mCallback(aCallback)
  {
    MOZ_COUNT_CTOR(ReadEvent);
  }

protected:
  ~ReadEvent()
  {
    MOZ_COUNT_DTOR(ReadEvent);
  }

public:
  NS_IMETHOD Run() override
  {
    nsresult rv;

    if (mHandle->IsClosed() || (mCallback && mCallback->IsKilled())) {
      rv = NS_ERROR_NOT_INITIALIZED;
    } else {
      rv = CacheFileIOManager::gInstance->ReadInternal(
        mHandle, mOffset, mBuf, mCount);
    }

    mCallback->OnDataRead(mHandle, mBuf, rv);
    return NS_OK;
  }

protected:
  RefPtr<CacheFileHandle>       mHandle;
  int64_t                       mOffset;
  char                         *mBuf;
  int32_t                       mCount;
  nsCOMPtr<CacheFileIOListener> mCallback;
};

class WriteEvent : public Runnable {
public:
  WriteEvent(CacheFileHandle *aHandle, int64_t aOffset, const char *aBuf,
             int32_t aCount, bool aValidate, bool aTruncate,
             CacheFileIOListener *aCallback)
    : mHandle(aHandle)
    , mOffset(aOffset)
    , mBuf(aBuf)
    , mCount(aCount)
    , mValidate(aValidate)
    , mTruncate(aTruncate)
    , mCallback(aCallback)
  {
    MOZ_COUNT_CTOR(WriteEvent);
  }

protected:
  ~WriteEvent()
  {
    MOZ_COUNT_DTOR(WriteEvent);

    if (!mCallback && mBuf) {
      free(const_cast<char *>(mBuf));
    }
  }

public:
  NS_IMETHOD Run() override
  {
    nsresult rv;

    if (mHandle->IsClosed() || (mCallback && mCallback->IsKilled())) {
      // We usually get here only after the internal shutdown
      // (i.e. mShuttingDown == true).  Pretend write has succeeded
      // to avoid any past-shutdown file dooming.
      rv = (CacheObserver::IsPastShutdownIOLag() ||
            CacheFileIOManager::gInstance->mShuttingDown)
        ? NS_OK
        : NS_ERROR_NOT_INITIALIZED;
    } else {
      rv = CacheFileIOManager::gInstance->WriteInternal(
          mHandle, mOffset, mBuf, mCount, mValidate, mTruncate);
      if (NS_FAILED(rv) && !mCallback) {
        // No listener is going to handle the error, doom the file
        CacheFileIOManager::gInstance->DoomFileInternal(mHandle);
      }
    }
    if (mCallback) {
      mCallback->OnDataWritten(mHandle, mBuf, rv);
    } else {
      free(const_cast<char *>(mBuf));
      mBuf = nullptr;
    }

    return NS_OK;
  }

protected:
  RefPtr<CacheFileHandle>       mHandle;
  int64_t                       mOffset;
  const char                   *mBuf;
  int32_t                       mCount;
  bool                          mValidate : 1;
  bool                          mTruncate : 1;
  nsCOMPtr<CacheFileIOListener> mCallback;
};

class DoomFileEvent : public Runnable {
public:
  DoomFileEvent(CacheFileHandle *aHandle,
                CacheFileIOListener *aCallback)
    : mCallback(aCallback)
    , mHandle(aHandle)
  {
    MOZ_COUNT_CTOR(DoomFileEvent);
  }

protected:
  ~DoomFileEvent()
  {
    MOZ_COUNT_DTOR(DoomFileEvent);
  }

public:
  NS_IMETHOD Run() override
  {
    nsresult rv;

    if (mHandle->IsClosed()) {
      rv = NS_ERROR_NOT_INITIALIZED;
    } else {
      rv = CacheFileIOManager::gInstance->DoomFileInternal(mHandle);
    }

    if (mCallback) {
      mCallback->OnFileDoomed(mHandle, rv);
    }

    return NS_OK;
  }

protected:
  nsCOMPtr<CacheFileIOListener>              mCallback;
  nsCOMPtr<nsIEventTarget>                   mTarget;
  RefPtr<CacheFileHandle>                    mHandle;
};

class DoomFileByKeyEvent : public Runnable {
public:
  DoomFileByKeyEvent(const nsACString &aKey,
                     CacheFileIOListener *aCallback)
    : mCallback(aCallback)
  {
    MOZ_COUNT_CTOR(DoomFileByKeyEvent);

    SHA1Sum sum;
    sum.update(aKey.BeginReading(), aKey.Length());
    sum.finish(mHash);

    mIOMan = CacheFileIOManager::gInstance;
  }

protected:
  ~DoomFileByKeyEvent()
  {
    MOZ_COUNT_DTOR(DoomFileByKeyEvent);
  }

public:
  NS_IMETHOD Run() override
  {
    nsresult rv;

    if (!mIOMan) {
      rv = NS_ERROR_NOT_INITIALIZED;
    } else {
      rv = mIOMan->DoomFileByKeyInternal(&mHash);
      mIOMan = nullptr;
    }

    if (mCallback) {
      mCallback->OnFileDoomed(nullptr, rv);
    }

    return NS_OK;
  }

protected:
  SHA1Sum::Hash                 mHash;
  nsCOMPtr<CacheFileIOListener> mCallback;
  RefPtr<CacheFileIOManager>    mIOMan;
};

class ReleaseNSPRHandleEvent : public Runnable {
public:
  explicit ReleaseNSPRHandleEvent(CacheFileHandle *aHandle)
    : mHandle(aHandle)
  {
    MOZ_COUNT_CTOR(ReleaseNSPRHandleEvent);
  }

protected:
  ~ReleaseNSPRHandleEvent()
  {
    MOZ_COUNT_DTOR(ReleaseNSPRHandleEvent);
  }

public:
  NS_IMETHOD Run() override
  {
    if (!mHandle->IsClosed()) {
      CacheFileIOManager::gInstance->MaybeReleaseNSPRHandleInternal(mHandle);
    }

    return NS_OK;
  }

protected:
  RefPtr<CacheFileHandle>       mHandle;
};

class TruncateSeekSetEOFEvent : public Runnable {
public:
  TruncateSeekSetEOFEvent(CacheFileHandle *aHandle, int64_t aTruncatePos,
                          int64_t aEOFPos, CacheFileIOListener *aCallback)
    : mHandle(aHandle)
    , mTruncatePos(aTruncatePos)
    , mEOFPos(aEOFPos)
    , mCallback(aCallback)
  {
    MOZ_COUNT_CTOR(TruncateSeekSetEOFEvent);
  }

protected:
  ~TruncateSeekSetEOFEvent()
  {
    MOZ_COUNT_DTOR(TruncateSeekSetEOFEvent);
  }

public:
  NS_IMETHOD Run() override
  {
    nsresult rv;

    if (mHandle->IsClosed() || (mCallback && mCallback->IsKilled())) {
      rv = NS_ERROR_NOT_INITIALIZED;
    } else {
      rv = CacheFileIOManager::gInstance->TruncateSeekSetEOFInternal(
        mHandle, mTruncatePos, mEOFPos);
    }

    if (mCallback) {
      mCallback->OnEOFSet(mHandle, rv);
    }

    return NS_OK;
  }

protected:
  RefPtr<CacheFileHandle>       mHandle;
  int64_t                       mTruncatePos;
  int64_t                       mEOFPos;
  nsCOMPtr<CacheFileIOListener> mCallback;
};

class RenameFileEvent : public Runnable {
public:
  RenameFileEvent(CacheFileHandle *aHandle, const nsACString &aNewName,
                  CacheFileIOListener *aCallback)
    : mHandle(aHandle)
    , mNewName(aNewName)
    , mCallback(aCallback)
  {
    MOZ_COUNT_CTOR(RenameFileEvent);
  }

protected:
  ~RenameFileEvent()
  {
    MOZ_COUNT_DTOR(RenameFileEvent);
  }

public:
  NS_IMETHOD Run() override
  {
    nsresult rv;

    if (mHandle->IsClosed()) {
      rv = NS_ERROR_NOT_INITIALIZED;
    } else {
      rv = CacheFileIOManager::gInstance->RenameFileInternal(mHandle,
                                                             mNewName);
    }

    if (mCallback) {
      mCallback->OnFileRenamed(mHandle, rv);
    }

    return NS_OK;
  }

protected:
  RefPtr<CacheFileHandle>       mHandle;
  nsCString                     mNewName;
  nsCOMPtr<CacheFileIOListener> mCallback;
};

class InitIndexEntryEvent : public Runnable {
public:
  InitIndexEntryEvent(CacheFileHandle *aHandle,
                      OriginAttrsHash aOriginAttrsHash, bool aAnonymous,
                      bool aPinning)
    : mHandle(aHandle)
    , mOriginAttrsHash(aOriginAttrsHash)
    , mAnonymous(aAnonymous)
    , mPinning(aPinning)
  {
    MOZ_COUNT_CTOR(InitIndexEntryEvent);
  }

protected:
  ~InitIndexEntryEvent()
  {
    MOZ_COUNT_DTOR(InitIndexEntryEvent);
  }

public:
  NS_IMETHOD Run() override
  {
    if (mHandle->IsClosed() || mHandle->IsDoomed()) {
      return NS_OK;
    }

    CacheIndex::InitEntry(mHandle->Hash(), mOriginAttrsHash, mAnonymous,
                          mPinning);

    // We cannot set the filesize before we init the entry. If we're opening
    // an existing entry file, frecency and expiration time will be set after
    // parsing the entry file, but we must set the filesize here since nobody is
    // going to set it if there is no write to the file.
    uint32_t sizeInK = mHandle->FileSizeInK();
    CacheIndex::UpdateEntry(mHandle->Hash(), nullptr, nullptr, &sizeInK);

    return NS_OK;
  }

protected:
  RefPtr<CacheFileHandle> mHandle;
  OriginAttrsHash         mOriginAttrsHash;
  bool                    mAnonymous;
  bool                    mPinning;
};

class UpdateIndexEntryEvent : public Runnable {
public:
  UpdateIndexEntryEvent(CacheFileHandle *aHandle, const uint32_t *aFrecency,
                        const uint32_t *aExpirationTime)
    : mHandle(aHandle)
    , mHasFrecency(false)
    , mHasExpirationTime(false)
  {
    MOZ_COUNT_CTOR(UpdateIndexEntryEvent);
    if (aFrecency) {
      mHasFrecency = true;
      mFrecency = *aFrecency;
    }
    if (aExpirationTime) {
      mHasExpirationTime = true;
      mExpirationTime = *aExpirationTime;
    }
  }

protected:
  ~UpdateIndexEntryEvent()
  {
    MOZ_COUNT_DTOR(UpdateIndexEntryEvent);
  }

public:
  NS_IMETHOD Run() override
  {
    if (mHandle->IsClosed() || mHandle->IsDoomed()) {
      return NS_OK;
    }

    CacheIndex::UpdateEntry(mHandle->Hash(),
                            mHasFrecency ? &mFrecency : nullptr,
                            mHasExpirationTime ? &mExpirationTime : nullptr,
                            nullptr);
    return NS_OK;
  }

protected:
  RefPtr<CacheFileHandle> mHandle;
  bool                      mHasFrecency;
  bool                      mHasExpirationTime;
  uint32_t                  mFrecency;
  uint32_t                  mExpirationTime;
};

class MetadataWriteScheduleEvent : public Runnable
{
public:
  enum EMode {
    SCHEDULE,
    UNSCHEDULE,
    SHUTDOWN
  } mMode;

  RefPtr<CacheFile> mFile;
  RefPtr<CacheFileIOManager> mIOMan;

  MetadataWriteScheduleEvent(CacheFileIOManager * aManager,
                             CacheFile * aFile,
                             EMode aMode)
    : mMode(aMode)
    , mFile(aFile)
    , mIOMan(aManager)
  { }

  virtual ~MetadataWriteScheduleEvent() { }

  NS_IMETHOD Run() override
  {
    RefPtr<CacheFileIOManager> ioMan = CacheFileIOManager::gInstance;
    if (!ioMan) {
      NS_WARNING("CacheFileIOManager already gone in MetadataWriteScheduleEvent::Run()");
      return NS_OK;
    }

    switch (mMode)
    {
    case SCHEDULE:
      ioMan->ScheduleMetadataWriteInternal(mFile);
      break;
    case UNSCHEDULE:
      ioMan->UnscheduleMetadataWriteInternal(mFile);
      break;
    case SHUTDOWN:
      ioMan->ShutdownMetadataWriteSchedulingInternal();
      break;
    }
    return NS_OK;
  }
};

StaticRefPtr<CacheFileIOManager> CacheFileIOManager::gInstance;

NS_IMPL_ISUPPORTS(CacheFileIOManager, nsITimerCallback)

CacheFileIOManager::CacheFileIOManager()
  : mShuttingDown(false)
  , mTreeCreated(false)
  , mTreeCreationFailed(false)
  , mOverLimitEvicting(false)
  , mRemovingTrashDirs(false)
{
  LOG(("CacheFileIOManager::CacheFileIOManager [this=%p]", this));
  MOZ_COUNT_CTOR(CacheFileIOManager);
  MOZ_ASSERT(!gInstance, "multiple CacheFileIOManager instances!");
}

CacheFileIOManager::~CacheFileIOManager()
{
  LOG(("CacheFileIOManager::~CacheFileIOManager [this=%p]", this));
  MOZ_COUNT_DTOR(CacheFileIOManager);
}

// static
nsresult
CacheFileIOManager::Init()
{
  LOG(("CacheFileIOManager::Init()"));

  MOZ_ASSERT(NS_IsMainThread());

  if (gInstance) {
    return NS_ERROR_ALREADY_INITIALIZED;
  }

  RefPtr<CacheFileIOManager> ioMan = new CacheFileIOManager();

  nsresult rv = ioMan->InitInternal();
  NS_ENSURE_SUCCESS(rv, rv);

  gInstance = ioMan.forget();
  return NS_OK;
}

nsresult
CacheFileIOManager::InitInternal()
{
  nsresult rv;

  mIOThread = new CacheIOThread();

  rv = mIOThread->Init();
  MOZ_ASSERT(NS_SUCCEEDED(rv), "Can't create background thread");
  NS_ENSURE_SUCCESS(rv, rv);

  mStartTime = TimeStamp::NowLoRes();

  return NS_OK;
}

// static
nsresult
CacheFileIOManager::Shutdown()
{
  LOG(("CacheFileIOManager::Shutdown() [gInstance=%p]", gInstance.get()));

  MOZ_ASSERT(NS_IsMainThread());

  if (!gInstance) {
    return NS_ERROR_NOT_INITIALIZED;
  }

  CacheIndex::PreShutdown();

  ShutdownMetadataWriteScheduling();

  RefPtr<ShutdownEvent> ev = new ShutdownEvent();
  ev->PostAndWait();

  MOZ_ASSERT(gInstance->mHandles.HandleCount() == 0);
  MOZ_ASSERT(gInstance->mHandlesByLastUsed.Length() == 0);

  if (gInstance->mIOThread) {
    gInstance->mIOThread->Shutdown();
  }

  CacheIndex::Shutdown();

  if (CacheObserver::ClearCacheOnShutdown()) {
    gInstance->SyncRemoveAllCacheFiles();
  }

  gInstance = nullptr;

  return NS_OK;
}

nsresult
CacheFileIOManager::ShutdownInternal()
{
  LOG(("CacheFileIOManager::ShutdownInternal() [this=%p]", this));

  MOZ_ASSERT(mIOThread->IsCurrentThread());

  // No new handles can be created after this flag is set
  mShuttingDown = true;

  // close all handles and delete all associated files
  nsTArray<RefPtr<CacheFileHandle> > handles;
  mHandles.GetAllHandles(&handles);
  handles.AppendElements(mSpecialHandles);

  for (uint32_t i=0 ; i<handles.Length() ; i++) {
    CacheFileHandle *h = handles[i];
    h->mClosed = true;

    h->Log();

    // Close completely written files.
    MaybeReleaseNSPRHandleInternal(h);
    // Don't bother removing invalid and/or doomed files to improve
    // shutdown perfomrance.
    // Doomed files are already in the doomed directory from which
    // we never reuse files and delete the dir on next session startup.
    // Invalid files don't have metadata and thus won't load anyway
    // (hashes won't match).

    if (!h->IsSpecialFile() && !h->mIsDoomed && !h->mFileExists) {
      CacheIndex::RemoveEntry(h->Hash());
    }

    // Remove the handle from mHandles/mSpecialHandles
    if (h->IsSpecialFile()) {
      mSpecialHandles.RemoveElement(h);
    } else {
      mHandles.RemoveHandle(h);
    }

    // Pointer to the hash is no longer valid once the last handle with the
    // given hash is released. Null out the pointer so that we crash if there
    // is a bug in this code and we dereference the pointer after this point.
    if (!h->IsSpecialFile()) {
      h->mHash = nullptr;
    }
  }

  // Assert the table is empty. When we are here, no new handles can be added
  // and handles will no longer remove them self from this table and we don't
  // want to keep invalid handles here. Also, there is no lookup after this
  // point to happen.
  MOZ_ASSERT(mHandles.HandleCount() == 0);

  // Release trash directory enumerator
  if (mTrashDirEnumerator) {
    mTrashDirEnumerator->Close();
    mTrashDirEnumerator = nullptr;
  }

  return NS_OK;
}

// static
nsresult
CacheFileIOManager::OnProfile()
{
  LOG(("CacheFileIOManager::OnProfile() [gInstance=%p]", gInstance.get()));

  RefPtr<CacheFileIOManager> ioMan = gInstance;
  if (!ioMan) {
    // CacheFileIOManager::Init() failed, probably could not create the IO
    // thread, just go with it...
    return NS_ERROR_NOT_INITIALIZED;
  }

  nsresult rv;

  nsCOMPtr<nsIFile> directory;

  CacheObserver::ParentDirOverride(getter_AddRefs(directory));

  if (!directory) {
    rv = NS_GetSpecialDirectory(NS_APP_CACHE_PARENT_DIR,
                                getter_AddRefs(directory));
  }

  if (!directory) {
    rv = NS_GetSpecialDirectory(NS_APP_USER_PROFILE_LOCAL_50_DIR,
                                getter_AddRefs(directory));
  }

  if (directory) {
    rv = directory->Append(NS_LITERAL_STRING("cache2"));
    NS_ENSURE_SUCCESS(rv, rv);
  }

  // All functions return a clone.
  ioMan->mCacheDirectory.swap(directory);

  if (ioMan->mCacheDirectory) {
    CacheIndex::Init(ioMan->mCacheDirectory);
  }

  return NS_OK;
}

// static
already_AddRefed<nsIEventTarget>
CacheFileIOManager::IOTarget()
{
  nsCOMPtr<nsIEventTarget> target;
  if (gInstance && gInstance->mIOThread) {
    target = gInstance->mIOThread->Target();
  }

  return target.forget();
}

// static
already_AddRefed<CacheIOThread>
CacheFileIOManager::IOThread()
{
  RefPtr<CacheIOThread> thread;
  if (gInstance) {
    thread = gInstance->mIOThread;
  }

  return thread.forget();
}

// static
bool
CacheFileIOManager::IsOnIOThread()
{
  RefPtr<CacheFileIOManager> ioMan = gInstance;
  if (ioMan && ioMan->mIOThread) {
    return ioMan->mIOThread->IsCurrentThread();
  }

  return false;
}

// static
bool
CacheFileIOManager::IsOnIOThreadOrCeased()
{
  RefPtr<CacheFileIOManager> ioMan = gInstance;
  if (ioMan && ioMan->mIOThread) {
    return ioMan->mIOThread->IsCurrentThread();
  }

  // Ceased...
  return true;
}

// static
bool
CacheFileIOManager::IsShutdown()
{
  if (!gInstance) {
    return true;
  }
  return gInstance->mShuttingDown;
}

// static
nsresult
CacheFileIOManager::ScheduleMetadataWrite(CacheFile * aFile)
{
  RefPtr<CacheFileIOManager> ioMan = gInstance;
  NS_ENSURE_TRUE(ioMan, NS_ERROR_NOT_INITIALIZED);

  NS_ENSURE_TRUE(!ioMan->mShuttingDown, NS_ERROR_NOT_INITIALIZED);

  RefPtr<MetadataWriteScheduleEvent> event = new MetadataWriteScheduleEvent(
    ioMan, aFile, MetadataWriteScheduleEvent::SCHEDULE);
  nsCOMPtr<nsIEventTarget> target = ioMan->IOTarget();
  NS_ENSURE_TRUE(target, NS_ERROR_UNEXPECTED);
  return target->Dispatch(event, nsIEventTarget::DISPATCH_NORMAL);
}

nsresult
CacheFileIOManager::ScheduleMetadataWriteInternal(CacheFile * aFile)
{
  MOZ_ASSERT(IsOnIOThreadOrCeased());

  nsresult rv;

  if (!mMetadataWritesTimer) {
    mMetadataWritesTimer = do_CreateInstance("@mozilla.org/timer;1", &rv);
    NS_ENSURE_SUCCESS(rv, rv);

    rv = mMetadataWritesTimer->InitWithCallback(
      this, kMetadataWriteDelay, nsITimer::TYPE_ONE_SHOT);
    NS_ENSURE_SUCCESS(rv, rv);
  }

  if (mScheduledMetadataWrites.IndexOf(aFile) !=
      mScheduledMetadataWrites.NoIndex) {
    return NS_OK;
  }

  mScheduledMetadataWrites.AppendElement(aFile);

  return NS_OK;
}

// static
nsresult
CacheFileIOManager::UnscheduleMetadataWrite(CacheFile * aFile)
{
  RefPtr<CacheFileIOManager> ioMan = gInstance;
  NS_ENSURE_TRUE(ioMan, NS_ERROR_NOT_INITIALIZED);

  NS_ENSURE_TRUE(!ioMan->mShuttingDown, NS_ERROR_NOT_INITIALIZED);

  RefPtr<MetadataWriteScheduleEvent> event = new MetadataWriteScheduleEvent(
    ioMan, aFile, MetadataWriteScheduleEvent::UNSCHEDULE);
  nsCOMPtr<nsIEventTarget> target = ioMan->IOTarget();
  NS_ENSURE_TRUE(target, NS_ERROR_UNEXPECTED);
  return target->Dispatch(event, nsIEventTarget::DISPATCH_NORMAL);
}

nsresult
CacheFileIOManager::UnscheduleMetadataWriteInternal(CacheFile * aFile)
{
  MOZ_ASSERT(IsOnIOThreadOrCeased());

  mScheduledMetadataWrites.RemoveElement(aFile);

  if (mScheduledMetadataWrites.Length() == 0 &&
      mMetadataWritesTimer) {
    mMetadataWritesTimer->Cancel();
    mMetadataWritesTimer = nullptr;
  }

  return NS_OK;
}

// static
nsresult
CacheFileIOManager::ShutdownMetadataWriteScheduling()
{
  RefPtr<CacheFileIOManager> ioMan = gInstance;
  NS_ENSURE_TRUE(ioMan, NS_ERROR_NOT_INITIALIZED);

  RefPtr<MetadataWriteScheduleEvent> event = new MetadataWriteScheduleEvent(
    ioMan, nullptr, MetadataWriteScheduleEvent::SHUTDOWN);
  nsCOMPtr<nsIEventTarget> target = ioMan->IOTarget();
  NS_ENSURE_TRUE(target, NS_ERROR_UNEXPECTED);
  return target->Dispatch(event, nsIEventTarget::DISPATCH_NORMAL);
}

nsresult
CacheFileIOManager::ShutdownMetadataWriteSchedulingInternal()
{
  MOZ_ASSERT(IsOnIOThreadOrCeased());

  nsTArray<RefPtr<CacheFile> > files;
  files.SwapElements(mScheduledMetadataWrites);
  for (uint32_t i = 0; i < files.Length(); ++i) {
    CacheFile * file = files[i];
    file->WriteMetadataIfNeeded();
  }

  if (mMetadataWritesTimer) {
    mMetadataWritesTimer->Cancel();
    mMetadataWritesTimer = nullptr;
  }

  return NS_OK;
}

NS_IMETHODIMP
CacheFileIOManager::Notify(nsITimer * aTimer)
{
  MOZ_ASSERT(IsOnIOThreadOrCeased());
  MOZ_ASSERT(mMetadataWritesTimer == aTimer);

  mMetadataWritesTimer = nullptr;

  nsTArray<RefPtr<CacheFile> > files;
  files.SwapElements(mScheduledMetadataWrites);
  for (uint32_t i = 0; i < files.Length(); ++i) {
    CacheFile * file = files[i];
    file->WriteMetadataIfNeeded();
  }

  return NS_OK;
}

// static
nsresult
CacheFileIOManager::OpenFile(const nsACString &aKey,
                             uint32_t aFlags, CacheFileIOListener *aCallback)
{
  LOG(("CacheFileIOManager::OpenFile() [key=%s, flags=%d, listener=%p]",
       PromiseFlatCString(aKey).get(), aFlags, aCallback));

  nsresult rv;
  RefPtr<CacheFileIOManager> ioMan = gInstance;

  if (!ioMan) {
    return NS_ERROR_NOT_INITIALIZED;
  }

  bool priority = aFlags & CacheFileIOManager::PRIORITY;
  RefPtr<OpenFileEvent> ev = new OpenFileEvent(aKey, aFlags, aCallback);
  rv = ioMan->mIOThread->Dispatch(ev, priority
    ? CacheIOThread::OPEN_PRIORITY
    : CacheIOThread::OPEN);
  NS_ENSURE_SUCCESS(rv, rv);

  return NS_OK;
}

nsresult
CacheFileIOManager::OpenFileInternal(const SHA1Sum::Hash *aHash,
                                     const nsACString &aKey,
                                     uint32_t aFlags,
                                     CacheFileHandle **_retval)
{
  LOG(("CacheFileIOManager::OpenFileInternal() [hash=%08x%08x%08x%08x%08x, "
       "key=%s, flags=%d]", LOGSHA1(aHash), PromiseFlatCString(aKey).get(),
       aFlags));

  MOZ_ASSERT(CacheFileIOManager::IsOnIOThread());

  nsresult rv;

  if (mShuttingDown) {
    return NS_ERROR_NOT_INITIALIZED;
  }

  CacheIOThread::Cancelable cancelable(true /* never called for special handles */);

  if (!mTreeCreated) {
    rv = CreateCacheTree();
    if (NS_FAILED(rv)) return rv;
  }

  CacheFileHandle::PinningStatus pinning = aFlags & PINNED
    ? CacheFileHandle::PinningStatus::PINNED
    : CacheFileHandle::PinningStatus::NON_PINNED;

  nsCOMPtr<nsIFile> file;
  rv = GetFile(aHash, getter_AddRefs(file));
  NS_ENSURE_SUCCESS(rv, rv);

  RefPtr<CacheFileHandle> handle;
  mHandles.GetHandle(aHash, getter_AddRefs(handle));

  if ((aFlags & (OPEN | CREATE | CREATE_NEW)) == CREATE_NEW) {
    if (handle) {
      rv = DoomFileInternal(handle);
      NS_ENSURE_SUCCESS(rv, rv);
      handle = nullptr;
    }

    rv = mHandles.NewHandle(aHash, aFlags & PRIORITY, pinning, getter_AddRefs(handle));
    NS_ENSURE_SUCCESS(rv, rv);

    bool exists;
    rv = file->Exists(&exists);
    NS_ENSURE_SUCCESS(rv, rv);

    if (exists) {
      CacheIndex::RemoveEntry(aHash);

      LOG(("CacheFileIOManager::OpenFileInternal() - Removing old file from "
           "disk"));
      rv = file->Remove(false);
      if (NS_FAILED(rv)) {
        NS_WARNING("Cannot remove old entry from the disk");
        LOG(("CacheFileIOManager::OpenFileInternal() - Removing old file failed"
             ". [rv=0x%08x]", rv));
      }
    }

    CacheIndex::AddEntry(aHash);
    handle->mFile.swap(file);
    handle->mFileSize = 0;
  }

  if (handle) {
    handle.swap(*_retval);
    return NS_OK;
  }

  bool exists, evictedAsPinned = false, evictedAsNonPinned = false;
  rv = file->Exists(&exists);
  NS_ENSURE_SUCCESS(rv, rv);

  if (exists && mContextEvictor) {
    if (mContextEvictor->ContextsCount() == 0) {
      mContextEvictor = nullptr;
    } else {
      mContextEvictor->WasEvicted(aKey, file, &evictedAsPinned, &evictedAsNonPinned);
    }
  }

  if (!exists && (aFlags & (OPEN | CREATE | CREATE_NEW)) == OPEN) {
    return NS_ERROR_NOT_AVAILABLE;
  }

  if (exists) {
    // For existing files we determine the pinning status later, after the metadata gets parsed.
    pinning = CacheFileHandle::PinningStatus::UNKNOWN;
  }

  rv = mHandles.NewHandle(aHash, aFlags & PRIORITY, pinning, getter_AddRefs(handle));
  NS_ENSURE_SUCCESS(rv, rv);

  if (exists) {
    // If this file has been found evicted through the context file evictor above for
    // any of pinned or non-pinned state, these calls ensure we doom the handle ASAP
    // we know the real pinning state after metadta has been parsed.  DoomFileInternal
    // on the |handle| doesn't doom right now, since the pinning state is unknown
    // and we pass down a pinning restriction.
    if (evictedAsPinned) {
      rv = DoomFileInternal(handle, DOOM_WHEN_PINNED);
      MOZ_ASSERT(!handle->IsDoomed() && NS_SUCCEEDED(rv));
    }
    if (evictedAsNonPinned) {
      rv = DoomFileInternal(handle, DOOM_WHEN_NON_PINNED);
      MOZ_ASSERT(!handle->IsDoomed() && NS_SUCCEEDED(rv));
    }

    rv = file->GetFileSize(&handle->mFileSize);
    NS_ENSURE_SUCCESS(rv, rv);

    handle->mFileExists = true;

    CacheIndex::EnsureEntryExists(aHash);
  } else {
    handle->mFileSize = 0;

    CacheIndex::AddEntry(aHash);
  }

  handle->mFile.swap(file);
  handle.swap(*_retval);
  return NS_OK;
}

nsresult
CacheFileIOManager::OpenSpecialFileInternal(const nsACString &aKey,
                                            uint32_t aFlags,
                                            CacheFileHandle **_retval)
{
  LOG(("CacheFileIOManager::OpenSpecialFileInternal() [key=%s, flags=%d]",
       PromiseFlatCString(aKey).get(), aFlags));

  MOZ_ASSERT(CacheFileIOManager::IsOnIOThread());

  nsresult rv;

  if (mShuttingDown) {
    return NS_ERROR_NOT_INITIALIZED;
  }

  if (!mTreeCreated) {
    rv = CreateCacheTree();
    if (NS_FAILED(rv)) return rv;
  }

  nsCOMPtr<nsIFile> file;
  rv = GetSpecialFile(aKey, getter_AddRefs(file));
  NS_ENSURE_SUCCESS(rv, rv);

  RefPtr<CacheFileHandle> handle;
  for (uint32_t i = 0 ; i < mSpecialHandles.Length() ; i++) {
    if (!mSpecialHandles[i]->IsDoomed() && mSpecialHandles[i]->Key() == aKey) {
      handle = mSpecialHandles[i];
      break;
    }
  }

  if ((aFlags & (OPEN | CREATE | CREATE_NEW)) == CREATE_NEW) {
    if (handle) {
      rv = DoomFileInternal(handle);
      NS_ENSURE_SUCCESS(rv, rv);
      handle = nullptr;
    }

    handle = new CacheFileHandle(aKey, aFlags & PRIORITY, CacheFileHandle::PinningStatus::NON_PINNED);
    mSpecialHandles.AppendElement(handle);

    bool exists;
    rv = file->Exists(&exists);
    NS_ENSURE_SUCCESS(rv, rv);

    if (exists) {
      LOG(("CacheFileIOManager::OpenSpecialFileInternal() - Removing file from "
           "disk"));
      rv = file->Remove(false);
      if (NS_FAILED(rv)) {
        NS_WARNING("Cannot remove old entry from the disk");
        LOG(("CacheFileIOManager::OpenSpecialFileInternal() - Removing file "
             "failed. [rv=0x%08x]", rv));
      }
    }

    handle->mFile.swap(file);
    handle->mFileSize = 0;
  }

  if (handle) {
    handle.swap(*_retval);
    return NS_OK;
  }

  bool exists;
  rv = file->Exists(&exists);
  NS_ENSURE_SUCCESS(rv, rv);

  if (!exists && (aFlags & (OPEN | CREATE | CREATE_NEW)) == OPEN) {
    return NS_ERROR_NOT_AVAILABLE;
  }

  handle = new CacheFileHandle(aKey, aFlags & PRIORITY, CacheFileHandle::PinningStatus::NON_PINNED);
  mSpecialHandles.AppendElement(handle);

  if (exists) {
    rv = file->GetFileSize(&handle->mFileSize);
    NS_ENSURE_SUCCESS(rv, rv);

    handle->mFileExists = true;
  } else {
    handle->mFileSize = 0;
  }

  handle->mFile.swap(file);
  handle.swap(*_retval);
  return NS_OK;
}

nsresult
CacheFileIOManager::CloseHandleInternal(CacheFileHandle *aHandle)
{
  nsresult rv;

  LOG(("CacheFileIOManager::CloseHandleInternal() [handle=%p]", aHandle));

  MOZ_ASSERT(!aHandle->IsClosed());

  aHandle->Log();

  MOZ_ASSERT(CacheFileIOManager::IsOnIOThreadOrCeased());

  CacheIOThread::Cancelable cancelable(!aHandle->IsSpecialFile());

  // Maybe close file handle (can be legally bypassed after shutdown)
  rv = MaybeReleaseNSPRHandleInternal(aHandle);

  // Delete the file if the entry was doomed or invalid and
  // filedesc properly closed
  if ((aHandle->mIsDoomed || aHandle->mInvalid) && NS_SUCCEEDED(rv)) {
    LOG(("CacheFileIOManager::CloseHandleInternal() - Removing file from "
         "disk"));

    aHandle->mFile->Remove(false);
  }

  if (!aHandle->IsSpecialFile() && !aHandle->mIsDoomed &&
      (aHandle->mInvalid || !aHandle->mFileExists)) {
    CacheIndex::RemoveEntry(aHandle->Hash());
  }

  // Don't remove handles after shutdown
  if (!mShuttingDown) {
    if (aHandle->IsSpecialFile()) {
      mSpecialHandles.RemoveElement(aHandle);
    } else {
      mHandles.RemoveHandle(aHandle);
    }
  }

  return NS_OK;
}

// static
nsresult
CacheFileIOManager::Read(CacheFileHandle *aHandle, int64_t aOffset,
                         char *aBuf, int32_t aCount,
                         CacheFileIOListener *aCallback)
{
  LOG(("CacheFileIOManager::Read() [handle=%p, offset=%lld, count=%d, "
       "listener=%p]", aHandle, aOffset, aCount, aCallback));

  if (CacheObserver::ShuttingDown()) {
    LOG(("  no reads after shutdown"));
    return NS_ERROR_NOT_INITIALIZED;
  }

  nsresult rv;
  RefPtr<CacheFileIOManager> ioMan = gInstance;

  if (aHandle->IsClosed() || !ioMan) {
    return NS_ERROR_NOT_INITIALIZED;
  }

  RefPtr<ReadEvent> ev = new ReadEvent(aHandle, aOffset, aBuf, aCount,
                                         aCallback);
  rv = ioMan->mIOThread->Dispatch(ev, aHandle->IsPriority()
    ? CacheIOThread::READ_PRIORITY
    : CacheIOThread::READ);
  NS_ENSURE_SUCCESS(rv, rv);

  return NS_OK;
}

nsresult
CacheFileIOManager::ReadInternal(CacheFileHandle *aHandle, int64_t aOffset,
                                 char *aBuf, int32_t aCount)
{
  LOG(("CacheFileIOManager::ReadInternal() [handle=%p, offset=%lld, count=%d]",
       aHandle, aOffset, aCount));

  nsresult rv;

  if (CacheObserver::ShuttingDown()) {
    LOG(("  no reads after shutdown"));
    return NS_ERROR_NOT_INITIALIZED;
  }

  if (!aHandle->mFileExists) {
    NS_WARNING("Trying to read from non-existent file");
    return NS_ERROR_NOT_AVAILABLE;
  }

  CacheIOThread::Cancelable cancelable(!aHandle->IsSpecialFile());

  if (!aHandle->mFD) {
    rv = OpenNSPRHandle(aHandle);
    NS_ENSURE_SUCCESS(rv, rv);
  } else {
    NSPRHandleUsed(aHandle);
  }

  // Check again, OpenNSPRHandle could figure out the file was gone.
  if (!aHandle->mFileExists) {
    NS_WARNING("Trying to read from non-existent file");
    return NS_ERROR_NOT_AVAILABLE;
  }

  int64_t offset = PR_Seek64(aHandle->mFD, aOffset, PR_SEEK_SET);
  if (offset == -1) {
    return NS_ERROR_FAILURE;
  }

  int32_t bytesRead = PR_Read(aHandle->mFD, aBuf, aCount);
  if (bytesRead != aCount) {
    return NS_ERROR_FAILURE;
  }

  return NS_OK;
}

// static
nsresult
CacheFileIOManager::Write(CacheFileHandle *aHandle, int64_t aOffset,
                          const char *aBuf, int32_t aCount, bool aValidate,
                          bool aTruncate, CacheFileIOListener *aCallback)
{
  LOG(("CacheFileIOManager::Write() [handle=%p, offset=%lld, count=%d, "
       "validate=%d, truncate=%d, listener=%p]", aHandle, aOffset, aCount,
       aValidate, aTruncate, aCallback));

  nsresult rv;
  RefPtr<CacheFileIOManager> ioMan = gInstance;

  if (aHandle->IsClosed() || (aCallback && aCallback->IsKilled()) || !ioMan) {
    if (!aCallback) {
      // When no callback is provided, CacheFileIOManager is responsible for
      // releasing the buffer. We must release it even in case of failure.
      free(const_cast<char *>(aBuf));
    }
    return NS_ERROR_NOT_INITIALIZED;
  }

  RefPtr<WriteEvent> ev = new WriteEvent(aHandle, aOffset, aBuf, aCount,
                                           aValidate, aTruncate, aCallback);
  rv = ioMan->mIOThread->Dispatch(ev, aHandle->mPriority
                                  ? CacheIOThread::WRITE_PRIORITY
                                  : CacheIOThread::WRITE);
  NS_ENSURE_SUCCESS(rv, rv);

  return NS_OK;
}

static nsresult
TruncFile(PRFileDesc *aFD, int64_t aEOF)
{
#if defined(XP_UNIX)
  if (ftruncate(PR_FileDesc2NativeHandle(aFD), aEOF) != 0) {
    NS_ERROR("ftruncate failed");
    return NS_ERROR_FAILURE;
  }
#elif defined(XP_WIN)
  int64_t cnt = PR_Seek64(aFD, aEOF, PR_SEEK_SET);
  if (cnt == -1) {
    return NS_ERROR_FAILURE;
  }
  if (!SetEndOfFile((HANDLE) PR_FileDesc2NativeHandle(aFD))) {
    NS_ERROR("SetEndOfFile failed");
    return NS_ERROR_FAILURE;
  }
#else
  MOZ_ASSERT(false, "Not implemented!");
  return NS_ERROR_NOT_IMPLEMENTED;
#endif

  return NS_OK;
}

nsresult
CacheFileIOManager::WriteInternal(CacheFileHandle *aHandle, int64_t aOffset,
                                  const char *aBuf, int32_t aCount,
                                  bool aValidate, bool aTruncate)
{
  LOG(("CacheFileIOManager::WriteInternal() [handle=%p, offset=%lld, count=%d, "
       "validate=%d, truncate=%d]", aHandle, aOffset, aCount, aValidate,
       aTruncate));

  nsresult rv;

  if (aHandle->mKilled) {
    LOG(("  handle already killed, nothing written"));
    return NS_OK;
  }

  if (CacheObserver::ShuttingDown() && (!aValidate || !aHandle->mFD)) {
    aHandle->mKilled = true;
    LOG(("  killing the handle, nothing written"));
    return NS_OK;
  }

  if (CacheObserver::IsPastShutdownIOLag()) {
    LOG(("  past the shutdown I/O lag, nothing written"));
    // Pretend the write has succeeded, otherwise upper layers will doom
    // the file and we end up with I/O anyway.
    return NS_OK;
  }

  CacheIOThread::Cancelable cancelable(!aHandle->IsSpecialFile());

  if (!aHandle->mFileExists) {
    rv = CreateFile(aHandle);
    NS_ENSURE_SUCCESS(rv, rv);
  }

  if (!aHandle->mFD) {
    rv = OpenNSPRHandle(aHandle);
    NS_ENSURE_SUCCESS(rv, rv);
  } else {
    NSPRHandleUsed(aHandle);
  }

  // Check again, OpenNSPRHandle could figure out the file was gone.
  if (!aHandle->mFileExists) {
    return NS_ERROR_NOT_AVAILABLE;
  }

  // Check whether this write would cause critical low disk space.
  if (aHandle->mFileSize < aOffset + aCount) {
    int64_t freeSpace = -1;
    rv = mCacheDirectory->GetDiskSpaceAvailable(&freeSpace);
    if (NS_WARN_IF(NS_FAILED(rv))) {
      LOG(("CacheFileIOManager::WriteInternal() - GetDiskSpaceAvailable() "
           "failed! [rv=0x%08x]", rv));
    } else {
      uint32_t limit = CacheObserver::DiskFreeSpaceHardLimit();
      if (freeSpace - aOffset - aCount + aHandle->mFileSize < limit) {
        LOG(("CacheFileIOManager::WriteInternal() - Low free space, refusing "
             "to write! [freeSpace=%lld, limit=%u]", freeSpace, limit));
        return NS_ERROR_FILE_DISK_FULL;
      }
    }
  }

  // Write invalidates the entry by default
  aHandle->mInvalid = true;

  int64_t offset = PR_Seek64(aHandle->mFD, aOffset, PR_SEEK_SET);
  if (offset == -1) {
    return NS_ERROR_FAILURE;
  }

  int32_t bytesWritten = PR_Write(aHandle->mFD, aBuf, aCount);

  if (bytesWritten != -1) {
    uint32_t oldSizeInK = aHandle->FileSizeInK();
    int64_t writeEnd = aOffset + bytesWritten;

    if (aTruncate) {
      rv = TruncFile(aHandle->mFD, writeEnd);
      NS_ENSURE_SUCCESS(rv, rv);

      aHandle->mFileSize = writeEnd;
    } else {
      if (aHandle->mFileSize < writeEnd) {
        aHandle->mFileSize = writeEnd;
      }
    }

    uint32_t newSizeInK = aHandle->FileSizeInK();

    if (oldSizeInK != newSizeInK && !aHandle->IsDoomed() &&
        !aHandle->IsSpecialFile()) {
      CacheIndex::UpdateEntry(aHandle->Hash(), nullptr, nullptr, &newSizeInK);

      if (oldSizeInK < newSizeInK) {
        EvictIfOverLimitInternal();
      }
    }
  }

  if (bytesWritten != aCount) {
    return NS_ERROR_FAILURE;
  }

  // Write was successful and this write validates the entry (i.e. metadata)
  if (aValidate) {
    aHandle->mInvalid = false;
  }

  return NS_OK;
}

// static
nsresult
CacheFileIOManager::DoomFile(CacheFileHandle *aHandle,
                             CacheFileIOListener *aCallback)
{
  LOG(("CacheFileIOManager::DoomFile() [handle=%p, listener=%p]",
       aHandle, aCallback));

  nsresult rv;
  RefPtr<CacheFileIOManager> ioMan = gInstance;

  if (aHandle->IsClosed() || !ioMan) {
    return NS_ERROR_NOT_INITIALIZED;
  }

  RefPtr<DoomFileEvent> ev = new DoomFileEvent(aHandle, aCallback);
  rv = ioMan->mIOThread->Dispatch(ev, aHandle->IsPriority()
    ? CacheIOThread::OPEN_PRIORITY
    : CacheIOThread::OPEN);
  NS_ENSURE_SUCCESS(rv, rv);

  return NS_OK;
}

nsresult
CacheFileIOManager::DoomFileInternal(CacheFileHandle *aHandle,
                                     PinningDoomRestriction aPinningDoomRestriction)
{
  LOG(("CacheFileIOManager::DoomFileInternal() [handle=%p]", aHandle));
  aHandle->Log();

  MOZ_ASSERT(CacheFileIOManager::IsOnIOThreadOrCeased());

  nsresult rv;

  if (aHandle->IsDoomed()) {
    return NS_OK;
  }

  CacheIOThread::Cancelable cancelable(!aHandle->IsSpecialFile());

  if (aPinningDoomRestriction > NO_RESTRICTION) {
    switch (aHandle->mPinning) {
    case CacheFileHandle::PinningStatus::NON_PINNED:
      if (MOZ_LIKELY(aPinningDoomRestriction != DOOM_WHEN_NON_PINNED)) {
        LOG(("  not dooming, it's a non-pinned handle"));
        return NS_OK;
      }
      // Doom now
      break;

    case CacheFileHandle::PinningStatus::PINNED:
      if (MOZ_UNLIKELY(aPinningDoomRestriction != DOOM_WHEN_PINNED)) {
        LOG(("  not dooming, it's a pinned handle"));
        return NS_OK;
      }
      // Doom now
      break;

    case CacheFileHandle::PinningStatus::UNKNOWN:
      if (MOZ_LIKELY(aPinningDoomRestriction == DOOM_WHEN_NON_PINNED)) {
        LOG(("  doom when non-pinned set"));
        aHandle->mDoomWhenFoundNonPinned = true;
      } else if (MOZ_UNLIKELY(aPinningDoomRestriction == DOOM_WHEN_PINNED)) {
        LOG(("  doom when pinned set"));
        aHandle->mDoomWhenFoundPinned = true;
      }

      LOG(("  pinning status not known, deferring doom decision"));
      return NS_OK;
    }
  }

  if (aHandle->mFileExists) {
    // we need to move the current file to the doomed directory
    rv = MaybeReleaseNSPRHandleInternal(aHandle, true);
    NS_ENSURE_SUCCESS(rv, rv);

    // find unused filename
    nsCOMPtr<nsIFile> file;
    rv = GetDoomedFile(getter_AddRefs(file));
    NS_ENSURE_SUCCESS(rv, rv);

    nsCOMPtr<nsIFile> parentDir;
    rv = file->GetParent(getter_AddRefs(parentDir));
    NS_ENSURE_SUCCESS(rv, rv);

    nsAutoCString leafName;
    rv = file->GetNativeLeafName(leafName);
    NS_ENSURE_SUCCESS(rv, rv);

    rv = aHandle->mFile->MoveToNative(parentDir, leafName);
    if (NS_ERROR_FILE_NOT_FOUND == rv || NS_ERROR_FILE_TARGET_DOES_NOT_EXIST == rv) {
      LOG(("  file already removed under our hands"));
      aHandle->mFileExists = false;
      rv = NS_OK;
    } else {
      NS_ENSURE_SUCCESS(rv, rv);
      aHandle->mFile.swap(file);
    }
  }

  if (!aHandle->IsSpecialFile()) {
    CacheIndex::RemoveEntry(aHandle->Hash());
  }

  aHandle->mIsDoomed = true;

  if (!aHandle->IsSpecialFile()) {
    RefPtr<CacheStorageService> storageService = CacheStorageService::Self();
    if (storageService) {
      nsAutoCString idExtension, url;
      nsCOMPtr<nsILoadContextInfo> info =
        CacheFileUtils::ParseKey(aHandle->Key(), &idExtension, &url);
      MOZ_ASSERT(info);
      if (info) {
        storageService->CacheFileDoomed(info, idExtension, url);
      }
    }
  }

  return NS_OK;
}

// static
nsresult
CacheFileIOManager::DoomFileByKey(const nsACString &aKey,
                                  CacheFileIOListener *aCallback)
{
  LOG(("CacheFileIOManager::DoomFileByKey() [key=%s, listener=%p]",
       PromiseFlatCString(aKey).get(), aCallback));

  nsresult rv;
  RefPtr<CacheFileIOManager> ioMan = gInstance;

  if (!ioMan) {
    return NS_ERROR_NOT_INITIALIZED;
  }

  RefPtr<DoomFileByKeyEvent> ev = new DoomFileByKeyEvent(aKey, aCallback);
  rv = ioMan->mIOThread->DispatchAfterPendingOpens(ev);
  NS_ENSURE_SUCCESS(rv, rv);

  return NS_OK;
}

nsresult
CacheFileIOManager::DoomFileByKeyInternal(const SHA1Sum::Hash *aHash)
{
  LOG(("CacheFileIOManager::DoomFileByKeyInternal() [hash=%08x%08x%08x%08x%08x]"
       , LOGSHA1(aHash)));

  MOZ_ASSERT(CacheFileIOManager::IsOnIOThreadOrCeased());

  nsresult rv;

  if (mShuttingDown) {
    return NS_ERROR_NOT_INITIALIZED;
  }

  if (!mCacheDirectory) {
    return NS_ERROR_FILE_INVALID_PATH;
  }

  // Find active handle
  RefPtr<CacheFileHandle> handle;
  mHandles.GetHandle(aHash, getter_AddRefs(handle));

  if (handle) {
    handle->Log();

    return DoomFileInternal(handle);
  }

  CacheIOThread::Cancelable cancelable(true);

  // There is no handle for this file, delete the file if exists
  nsCOMPtr<nsIFile> file;
  rv = GetFile(aHash, getter_AddRefs(file));
  NS_ENSURE_SUCCESS(rv, rv);

  bool exists;
  rv = file->Exists(&exists);
  NS_ENSURE_SUCCESS(rv, rv);

  if (!exists) {
    return NS_ERROR_NOT_AVAILABLE;
  }

  LOG(("CacheFileIOManager::DoomFileByKeyInternal() - Removing file from "
       "disk"));
  rv = file->Remove(false);
  if (NS_FAILED(rv)) {
    NS_WARNING("Cannot remove old entry from the disk");
    LOG(("CacheFileIOManager::DoomFileByKeyInternal() - Removing file failed. "
         "[rv=0x%08x]", rv));
  }

  CacheIndex::RemoveEntry(aHash);

  return NS_OK;
}

// static
nsresult
CacheFileIOManager::ReleaseNSPRHandle(CacheFileHandle *aHandle)
{
  LOG(("CacheFileIOManager::ReleaseNSPRHandle() [handle=%p]", aHandle));

  nsresult rv;
  RefPtr<CacheFileIOManager> ioMan = gInstance;

  if (aHandle->IsClosed() || !ioMan) {
    return NS_ERROR_NOT_INITIALIZED;
  }

  RefPtr<ReleaseNSPRHandleEvent> ev = new ReleaseNSPRHandleEvent(aHandle);
  rv = ioMan->mIOThread->Dispatch(ev, aHandle->mPriority
                                  ? CacheIOThread::WRITE_PRIORITY
                                  : CacheIOThread::WRITE);
  NS_ENSURE_SUCCESS(rv, rv);

  return NS_OK;
}

nsresult
CacheFileIOManager::MaybeReleaseNSPRHandleInternal(CacheFileHandle *aHandle,
                                                   bool aIgnoreShutdownLag)
{
  LOG(("CacheFileIOManager::MaybeReleaseNSPRHandleInternal() [handle=%p, ignore shutdown=%d]",
       aHandle, aIgnoreShutdownLag));

  MOZ_ASSERT(CacheFileIOManager::IsOnIOThreadOrCeased());

  if (aHandle->mFD) {
    DebugOnly<bool> found;
    found = mHandlesByLastUsed.RemoveElement(aHandle);
    MOZ_ASSERT(found);
  }

  PRFileDesc *fd = aHandle->mFD;
  aHandle->mFD = nullptr;

  // Leak invalid (w/o metadata) and doomed handles immediately after shutdown.
  // Leak other handles when past the shutdown time maximum lag.
  if (
#ifndef DEBUG
      ((aHandle->mInvalid || aHandle->mIsDoomed) &&
      MOZ_UNLIKELY(CacheObserver::ShuttingDown())) ||
#endif
      MOZ_UNLIKELY(!aIgnoreShutdownLag &&
                   CacheObserver::IsPastShutdownIOLag())) {
    // Don't bother closing this file.  Return a failure code from here will
    // cause any following IO operation on the file (mainly removal) to be
    // bypassed, which is what we want.
    // For mInvalid == true the entry will never be used, since it doesn't
    // have correct metadata, thus we don't need to worry about removing it.
    // For mIsDoomed == true the file is already in the doomed sub-dir and
    // will be removed on next session start.
    LOG(("  past the shutdown I/O lag, leaking file handle"));
    return NS_ERROR_ILLEGAL_DURING_SHUTDOWN;
  }

  if (!fd) {
    // The filedesc has already been closed before, just let go.
    return NS_OK;
  }

  CacheIOThread::Cancelable cancelable(!aHandle->IsSpecialFile());

  PRStatus status = PR_Close(fd);
  if (status != PR_SUCCESS) {
    LOG(("CacheFileIOManager::MaybeReleaseNSPRHandleInternal() "
         "failed to close [handle=%p, status=%u]", aHandle, status));
    return NS_ERROR_FAILURE;
  }

  LOG(("CacheFileIOManager::MaybeReleaseNSPRHandleInternal() DONE"));

  return NS_OK;
}

// static
nsresult
CacheFileIOManager::TruncateSeekSetEOF(CacheFileHandle *aHandle,
                                       int64_t aTruncatePos, int64_t aEOFPos,
                                       CacheFileIOListener *aCallback)
{
  LOG(("CacheFileIOManager::TruncateSeekSetEOF() [handle=%p, truncatePos=%lld, "
       "EOFPos=%lld, listener=%p]", aHandle, aTruncatePos, aEOFPos, aCallback));

  nsresult rv;
  RefPtr<CacheFileIOManager> ioMan = gInstance;

  if (aHandle->IsClosed() || (aCallback && aCallback->IsKilled()) || !ioMan) {
    return NS_ERROR_NOT_INITIALIZED;
  }

  RefPtr<TruncateSeekSetEOFEvent> ev = new TruncateSeekSetEOFEvent(
                                           aHandle, aTruncatePos, aEOFPos,
                                           aCallback);
  rv = ioMan->mIOThread->Dispatch(ev, aHandle->mPriority
                                  ? CacheIOThread::WRITE_PRIORITY
                                  : CacheIOThread::WRITE);
  NS_ENSURE_SUCCESS(rv, rv);

  return NS_OK;
}

// static
void CacheFileIOManager::GetCacheDirectory(nsIFile** result)
{
  *result = nullptr;

  RefPtr<CacheFileIOManager> ioMan = gInstance;
  if (!ioMan || !ioMan->mCacheDirectory) {
    return;
  }

  ioMan->mCacheDirectory->Clone(result);
}

// static
nsresult
CacheFileIOManager::GetEntryInfo(const SHA1Sum::Hash *aHash,
                                 CacheStorageService::EntryInfoCallback *aCallback)
{
  MOZ_ASSERT(CacheFileIOManager::IsOnIOThread());

  nsresult rv;

  RefPtr<CacheFileIOManager> ioMan = gInstance;
  if (!ioMan) {
    return NS_ERROR_NOT_INITIALIZED;
  }

  nsAutoCString enhanceId;
  nsAutoCString uriSpec;

  RefPtr<CacheFileHandle> handle;
  ioMan->mHandles.GetHandle(aHash, getter_AddRefs(handle));
  if (handle) {
    RefPtr<nsILoadContextInfo> info =
      CacheFileUtils::ParseKey(handle->Key(), &enhanceId, &uriSpec);

    MOZ_ASSERT(info);
    if (!info) {
      return NS_OK; // ignore
    }

    RefPtr<CacheStorageService> service = CacheStorageService::Self();
    if (!service) {
      return NS_ERROR_NOT_INITIALIZED;
    }

    // Invokes OnCacheEntryInfo when an existing entry is found
    if (service->GetCacheEntryInfo(info, enhanceId, uriSpec, aCallback)) {
      return NS_OK;
    }

    // When we are here, there is no existing entry and we need
    // to synchrnously load metadata from a disk file.
  }

  // Locate the actual file
  nsCOMPtr<nsIFile> file;
  ioMan->GetFile(aHash, getter_AddRefs(file));

  // Read metadata from the file synchronously
  RefPtr<CacheFileMetadata> metadata = new CacheFileMetadata();
  rv = metadata->SyncReadMetadata(file);
  if (NS_FAILED(rv)) {
    return NS_OK;
  }

  // Now get the context + enhance id + URL from the key.
  nsAutoCString key;
  metadata->GetKey(key);

  RefPtr<nsILoadContextInfo> info =
    CacheFileUtils::ParseKey(key, &enhanceId, &uriSpec);
  MOZ_ASSERT(info);
  if (!info) {
    return NS_OK;
  }

  // Pick all data to pass to the callback.
  int64_t dataSize = metadata->Offset();
  uint32_t fetchCount;
  if (NS_FAILED(metadata->GetFetchCount(&fetchCount))) {
    fetchCount = 0;
  }
  uint32_t expirationTime;
  if (NS_FAILED(metadata->GetExpirationTime(&expirationTime))) {
    expirationTime = 0;
  }
  uint32_t lastModified;
  if (NS_FAILED(metadata->GetLastModified(&lastModified))) {
    lastModified = 0;
  }

  // Call directly on the callback.
  aCallback->OnEntryInfo(uriSpec, enhanceId, dataSize, fetchCount,
                         lastModified, expirationTime, metadata->Pinned());

  return NS_OK;
}

nsresult
CacheFileIOManager::TruncateSeekSetEOFInternal(CacheFileHandle *aHandle,
                                               int64_t aTruncatePos,
                                               int64_t aEOFPos)
{
  LOG(("CacheFileIOManager::TruncateSeekSetEOFInternal() [handle=%p, "
       "truncatePos=%lld, EOFPos=%lld]", aHandle, aTruncatePos, aEOFPos));

  nsresult rv;

  if (aHandle->mKilled) {
    LOG(("  handle already killed, file not truncated"));
    return NS_OK;
  }

  if (CacheObserver::ShuttingDown() && !aHandle->mFD) {
    aHandle->mKilled = true;
    LOG(("  killing the handle, file not truncated"));
    return NS_OK;
  }

  CacheIOThread::Cancelable cancelable(!aHandle->IsSpecialFile());

  if (!aHandle->mFileExists) {
    rv = CreateFile(aHandle);
    NS_ENSURE_SUCCESS(rv, rv);
  }

  if (!aHandle->mFD) {
    rv = OpenNSPRHandle(aHandle);
    NS_ENSURE_SUCCESS(rv, rv);
  } else {
    NSPRHandleUsed(aHandle);
  }

  // Check again, OpenNSPRHandle could figure out the file was gone.
  if (!aHandle->mFileExists) {
    return NS_ERROR_NOT_AVAILABLE;
  }

  // Check whether this operation would cause critical low disk space.
  if (aHandle->mFileSize < aEOFPos) {
    int64_t freeSpace = -1;
    rv = mCacheDirectory->GetDiskSpaceAvailable(&freeSpace);
    if (NS_WARN_IF(NS_FAILED(rv))) {
      LOG(("CacheFileIOManager::TruncateSeekSetEOFInternal() - "
           "GetDiskSpaceAvailable() failed! [rv=0x%08x]", rv));
    } else {
      uint32_t limit = CacheObserver::DiskFreeSpaceHardLimit();
      if (freeSpace - aEOFPos + aHandle->mFileSize < limit) {
        LOG(("CacheFileIOManager::TruncateSeekSetEOFInternal() - Low free space"
             ", refusing to write! [freeSpace=%lld, limit=%u]", freeSpace,
             limit));
        return NS_ERROR_FILE_DISK_FULL;
      }
    }
  }

  // This operation always invalidates the entry
  aHandle->mInvalid = true;

  rv = TruncFile(aHandle->mFD, aTruncatePos);
  NS_ENSURE_SUCCESS(rv, rv);

  if (aTruncatePos != aEOFPos) {
    rv = TruncFile(aHandle->mFD, aEOFPos);
    NS_ENSURE_SUCCESS(rv, rv);
  }

  uint32_t oldSizeInK = aHandle->FileSizeInK();
  aHandle->mFileSize = aEOFPos;
  uint32_t newSizeInK = aHandle->FileSizeInK();

  if (oldSizeInK != newSizeInK && !aHandle->IsDoomed() &&
      !aHandle->IsSpecialFile()) {
    CacheIndex::UpdateEntry(aHandle->Hash(), nullptr, nullptr, &newSizeInK);

    if (oldSizeInK < newSizeInK) {
      EvictIfOverLimitInternal();
    }
  }

  return NS_OK;
}

// static
nsresult
CacheFileIOManager::RenameFile(CacheFileHandle *aHandle,
                               const nsACString &aNewName,
                               CacheFileIOListener *aCallback)
{
  LOG(("CacheFileIOManager::RenameFile() [handle=%p, newName=%s, listener=%p]",
       aHandle, PromiseFlatCString(aNewName).get(), aCallback));

  nsresult rv;
  RefPtr<CacheFileIOManager> ioMan = gInstance;

  if (aHandle->IsClosed() || !ioMan) {
    return NS_ERROR_NOT_INITIALIZED;
  }

  if (!aHandle->IsSpecialFile()) {
    return NS_ERROR_UNEXPECTED;
  }

  RefPtr<RenameFileEvent> ev = new RenameFileEvent(aHandle, aNewName,
                                                     aCallback);
  rv = ioMan->mIOThread->Dispatch(ev, aHandle->mPriority
                                  ? CacheIOThread::WRITE_PRIORITY
                                  : CacheIOThread::WRITE);
  NS_ENSURE_SUCCESS(rv, rv);

  return NS_OK;
}

nsresult
CacheFileIOManager::RenameFileInternal(CacheFileHandle *aHandle,
                                       const nsACString &aNewName)
{
  LOG(("CacheFileIOManager::RenameFileInternal() [handle=%p, newName=%s]",
       aHandle, PromiseFlatCString(aNewName).get()));

  nsresult rv;

  MOZ_ASSERT(aHandle->IsSpecialFile());

  if (aHandle->IsDoomed()) {
    return NS_ERROR_NOT_AVAILABLE;
  }

  // Doom old handle if it exists and is not doomed
  for (uint32_t i = 0 ; i < mSpecialHandles.Length() ; i++) {
    if (!mSpecialHandles[i]->IsDoomed() &&
        mSpecialHandles[i]->Key() == aNewName) {
      MOZ_ASSERT(aHandle != mSpecialHandles[i]);
      rv = DoomFileInternal(mSpecialHandles[i]);
      NS_ENSURE_SUCCESS(rv, rv);
      break;
    }
  }

  nsCOMPtr<nsIFile> file;
  rv = GetSpecialFile(aNewName, getter_AddRefs(file));
  NS_ENSURE_SUCCESS(rv, rv);

  bool exists;
  rv = file->Exists(&exists);
  NS_ENSURE_SUCCESS(rv, rv);

  if (exists) {
    LOG(("CacheFileIOManager::RenameFileInternal() - Removing old file from "
         "disk"));
    rv = file->Remove(false);
    if (NS_FAILED(rv)) {
      NS_WARNING("Cannot remove file from the disk");
      LOG(("CacheFileIOManager::RenameFileInternal() - Removing old file failed"
           ". [rv=0x%08x]", rv));
    }
  }

  if (!aHandle->FileExists()) {
    aHandle->mKey = aNewName;
    return NS_OK;
  }

  rv = MaybeReleaseNSPRHandleInternal(aHandle, true);
  NS_ENSURE_SUCCESS(rv, rv);

  rv = aHandle->mFile->MoveToNative(nullptr, aNewName);
  NS_ENSURE_SUCCESS(rv, rv);

  aHandle->mKey = aNewName;
  return NS_OK;
}

// static
nsresult
CacheFileIOManager::EvictIfOverLimit()
{
  LOG(("CacheFileIOManager::EvictIfOverLimit()"));

  nsresult rv;
  RefPtr<CacheFileIOManager> ioMan = gInstance;

  if (!ioMan) {
    return NS_ERROR_NOT_INITIALIZED;
  }

  nsCOMPtr<nsIRunnable> ev;
  ev = NewRunnableMethod(ioMan,
			 &CacheFileIOManager::EvictIfOverLimitInternal);

  rv = ioMan->mIOThread->Dispatch(ev, CacheIOThread::EVICT);
  NS_ENSURE_SUCCESS(rv, rv);

  return NS_OK;
}

nsresult
CacheFileIOManager::EvictIfOverLimitInternal()
{
  LOG(("CacheFileIOManager::EvictIfOverLimitInternal()"));

  nsresult rv;

  MOZ_ASSERT(mIOThread->IsCurrentThread());

  if (mShuttingDown) {
    return NS_ERROR_NOT_INITIALIZED;
  }

  if (mOverLimitEvicting) {
    LOG(("CacheFileIOManager::EvictIfOverLimitInternal() - Eviction already "
         "running."));
    return NS_OK;
  }

  CacheIOThread::Cancelable cancelable(true);

  int64_t freeSpace;
  rv = mCacheDirectory->GetDiskSpaceAvailable(&freeSpace);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    freeSpace = -1;

    // Do not change smart size.
    LOG(("CacheFileIOManager::EvictIfOverLimitInternal() - "
         "GetDiskSpaceAvailable() failed! [rv=0x%08x]", rv));
  } else {
    UpdateSmartCacheSize(freeSpace);
  }

  uint32_t cacheUsage;
  rv = CacheIndex::GetCacheSize(&cacheUsage);
  NS_ENSURE_SUCCESS(rv, rv);

  uint32_t cacheLimit = CacheObserver::DiskCacheCapacity() >> 10;
  uint32_t freeSpaceLimit = CacheObserver::DiskFreeSpaceSoftLimit();

  if (cacheUsage <= cacheLimit &&
      (freeSpace == -1 || freeSpace >= freeSpaceLimit)) {
    LOG(("CacheFileIOManager::EvictIfOverLimitInternal() - Cache size and free "
         "space in limits. [cacheSize=%ukB, cacheSizeLimit=%ukB, "
         "freeSpace=%lld, freeSpaceLimit=%u]", cacheUsage, cacheLimit,
         freeSpace, freeSpaceLimit));
    return NS_OK;
  }

  LOG(("CacheFileIOManager::EvictIfOverLimitInternal() - Cache size exceeded "
       "limit. Starting overlimit eviction. [cacheSize=%u, limit=%u]",
       cacheUsage, cacheLimit));

  nsCOMPtr<nsIRunnable> ev;
  ev = NewRunnableMethod(this,
			 &CacheFileIOManager::OverLimitEvictionInternal);

  rv = mIOThread->Dispatch(ev, CacheIOThread::EVICT);
  NS_ENSURE_SUCCESS(rv, rv);

  mOverLimitEvicting = true;
  return NS_OK;
}

nsresult
CacheFileIOManager::OverLimitEvictionInternal()
{
  LOG(("CacheFileIOManager::OverLimitEvictionInternal()"));

  nsresult rv;

  MOZ_ASSERT(mIOThread->IsCurrentThread());

  // mOverLimitEvicting is accessed only on IO thread, so we can set it to false
  // here and set it to true again once we dispatch another event that will
  // continue with the eviction. The reason why we do so is that we can fail
  // early anywhere in this method and the variable will contain a correct
  // value. Otherwise we would need to set it to false on every failing place.
  mOverLimitEvicting = false;

  if (mShuttingDown) {
    return NS_ERROR_NOT_INITIALIZED;
  }

  while (true) {
    int64_t freeSpace = -1;
    rv = mCacheDirectory->GetDiskSpaceAvailable(&freeSpace);
    if (NS_WARN_IF(NS_FAILED(rv))) {
      // Do not change smart size.
      LOG(("CacheFileIOManager::EvictIfOverLimitInternal() - "
           "GetDiskSpaceAvailable() failed! [rv=0x%08x]", rv));
    } else {
      UpdateSmartCacheSize(freeSpace);
    }

    uint32_t cacheUsage;
    rv = CacheIndex::GetCacheSize(&cacheUsage);
    NS_ENSURE_SUCCESS(rv, rv);

    uint32_t cacheLimit = CacheObserver::DiskCacheCapacity() >> 10;
    uint32_t freeSpaceLimit = CacheObserver::DiskFreeSpaceSoftLimit();

    if (cacheUsage > cacheLimit) {
      LOG(("CacheFileIOManager::OverLimitEvictionInternal() - Cache size over "
           "limit. [cacheSize=%u, limit=%u]", cacheUsage, cacheLimit));
    } else if (freeSpace != 1 && freeSpace < freeSpaceLimit) {
      LOG(("CacheFileIOManager::OverLimitEvictionInternal() - Free space under "
           "limit. [freeSpace=%lld, freeSpaceLimit=%u]", freeSpace,
           freeSpaceLimit));
    } else {
      LOG(("CacheFileIOManager::OverLimitEvictionInternal() - Cache size and "
           "free space in limits. [cacheSize=%ukB, cacheSizeLimit=%ukB, "
           "freeSpace=%lld, freeSpaceLimit=%u]", cacheUsage, cacheLimit,
           freeSpace, freeSpaceLimit));
      return NS_OK;
    }

    if (CacheIOThread::YieldAndRerun()) {
      LOG(("CacheFileIOManager::OverLimitEvictionInternal() - Breaking loop "
           "for higher level events."));
      mOverLimitEvicting = true;
      return NS_OK;
    }

    SHA1Sum::Hash hash;
    uint32_t cnt;
    static uint32_t consecutiveFailures = 0;
    rv = CacheIndex::GetEntryForEviction(false, &hash, &cnt);
    NS_ENSURE_SUCCESS(rv, rv);

    rv = DoomFileByKeyInternal(&hash);
    if (NS_SUCCEEDED(rv)) {
      consecutiveFailures = 0;
    } else if (rv == NS_ERROR_NOT_AVAILABLE) {
      LOG(("CacheFileIOManager::OverLimitEvictionInternal() - "
           "DoomFileByKeyInternal() failed. [rv=0x%08x]", rv));
      // TODO index is outdated, start update

      // Make sure index won't return the same entry again
      CacheIndex::RemoveEntry(&hash);
      consecutiveFailures = 0;
    } else {
      // This shouldn't normally happen, but the eviction must not fail
      // completely if we ever encounter this problem.
      NS_WARNING("CacheFileIOManager::OverLimitEvictionInternal() - Unexpected "
                 "failure of DoomFileByKeyInternal()");

      LOG(("CacheFileIOManager::OverLimitEvictionInternal() - "
           "DoomFileByKeyInternal() failed. [rv=0x%08x]", rv));

      // Normally, CacheIndex::UpdateEntry() is called only to update newly
      // created/opened entries which are always fresh and UpdateEntry() expects
      // and checks this flag. The way we use UpdateEntry() here is a kind of
      // hack and we must make sure the flag is set by calling
      // EnsureEntryExists().
      rv = CacheIndex::EnsureEntryExists(&hash);
      NS_ENSURE_SUCCESS(rv, rv);

      // Move the entry at the end of both lists to make sure we won't end up
      // failing on one entry forever.
      uint32_t frecency = 0;
      uint32_t expTime = nsICacheEntry::NO_EXPIRATION_TIME;
      rv = CacheIndex::UpdateEntry(&hash, &frecency, &expTime, nullptr);
      NS_ENSURE_SUCCESS(rv, rv);

      consecutiveFailures++;
      if (consecutiveFailures >= cnt) {
        // This doesn't necessarily mean that we've tried to doom every entry
        // but we've reached a sane number of tries. It is likely that another
        // eviction will start soon. And as said earlier, this normally doesn't
        // happen at all.
        return NS_OK;
      }
    }
  }

  NS_NOTREACHED("We should never get here");
  return NS_OK;
}

// static
nsresult
CacheFileIOManager::EvictAll()
{
  LOG(("CacheFileIOManager::EvictAll()"));

  nsresult rv;
  RefPtr<CacheFileIOManager> ioMan = gInstance;

  if (!ioMan) {
    return NS_ERROR_NOT_INITIALIZED;
  }

  nsCOMPtr<nsIRunnable> ev;
  ev = NewRunnableMethod(ioMan, &CacheFileIOManager::EvictAllInternal);

  rv = ioMan->mIOThread->DispatchAfterPendingOpens(ev);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  return NS_OK;
}

namespace {

class EvictionNotifierRunnable : public Runnable
{
public:
  NS_DECL_NSIRUNNABLE
};

NS_IMETHODIMP
EvictionNotifierRunnable::Run()
{
  nsCOMPtr<nsIObserverService> obsSvc = mozilla::services::GetObserverService();
  if (obsSvc) {
    obsSvc->NotifyObservers(nullptr, "cacheservice:empty-cache", nullptr);
  }
  return NS_OK;
}

} // namespace

nsresult
CacheFileIOManager::EvictAllInternal()
{
  LOG(("CacheFileIOManager::EvictAllInternal()"));

  nsresult rv;

  MOZ_ASSERT(mIOThread->IsCurrentThread());

  RefPtr<EvictionNotifierRunnable> r = new EvictionNotifierRunnable();

  if (!mCacheDirectory) {
    // This is a kind of hack. Somebody called EvictAll() without a profile.
    // This happens in xpcshell tests that use cache without profile. We need
    // to notify observers in this case since the tests are waiting for it.
    NS_DispatchToMainThread(r);
    return NS_ERROR_FILE_INVALID_PATH;
  }

  if (mShuttingDown) {
    return NS_ERROR_NOT_INITIALIZED;
  }

  if (!mTreeCreated) {
    rv = CreateCacheTree();
    if (NS_FAILED(rv)) {
      return rv;
    }
  }

  // Doom all active handles
  nsTArray<RefPtr<CacheFileHandle> > handles;
  mHandles.GetActiveHandles(&handles);

  for (uint32_t i = 0; i < handles.Length(); ++i) {
    rv = DoomFileInternal(handles[i]);
    if (NS_WARN_IF(NS_FAILED(rv))) {
      LOG(("CacheFileIOManager::EvictAllInternal() - Cannot doom handle "
           "[handle=%p]", handles[i].get()));
    }
  }

  nsCOMPtr<nsIFile> file;
  rv = mCacheDirectory->Clone(getter_AddRefs(file));
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  rv = file->AppendNative(NS_LITERAL_CSTRING(ENTRIES_DIR));
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  // Trash current entries directory
  rv = TrashDirectory(file);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  // Files are now inaccessible in entries directory, notify observers.
  NS_DispatchToMainThread(r);

  // Create a new empty entries directory
  rv = CheckAndCreateDir(mCacheDirectory, ENTRIES_DIR, false);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  CacheIndex::RemoveAll();

  return NS_OK;
}

// static
nsresult
CacheFileIOManager::EvictByContext(nsILoadContextInfo *aLoadContextInfo, bool aPinned)
{
  LOG(("CacheFileIOManager::EvictByContext() [loadContextInfo=%p]",
       aLoadContextInfo));

  nsresult rv;
  RefPtr<CacheFileIOManager> ioMan = gInstance;

  if (!ioMan) {
    return NS_ERROR_NOT_INITIALIZED;
  }

  nsCOMPtr<nsIRunnable> ev;
  ev = NewRunnableMethod<nsCOMPtr<nsILoadContextInfo>, bool>
         (ioMan, &CacheFileIOManager::EvictByContextInternal, aLoadContextInfo, aPinned);

  rv = ioMan->mIOThread->DispatchAfterPendingOpens(ev);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  return NS_OK;
}

nsresult
CacheFileIOManager::EvictByContextInternal(nsILoadContextInfo *aLoadContextInfo, bool aPinned)
{
  LOG(("CacheFileIOManager::EvictByContextInternal() [loadContextInfo=%p, pinned=%d]",
      aLoadContextInfo, aPinned));

  nsresult rv;

  if (aLoadContextInfo) {
    nsAutoCString suffix;
    aLoadContextInfo->OriginAttributesPtr()->CreateSuffix(suffix);
    LOG(("  anonymous=%u, suffix=%s]", aLoadContextInfo->IsAnonymous(), suffix.get()));

    MOZ_ASSERT(mIOThread->IsCurrentThread());

    MOZ_ASSERT(!aLoadContextInfo->IsPrivate());
    if (aLoadContextInfo->IsPrivate()) {
      return NS_ERROR_INVALID_ARG;
    }
  }

  if (!mCacheDirectory) {
    // This is a kind of hack. Somebody called EvictAll() without a profile.
    // This happens in xpcshell tests that use cache without profile. We need
    // to notify observers in this case since the tests are waiting for it.
    // Also notify for aPinned == true, those are interested as well.
    if (!aLoadContextInfo) {
      RefPtr<EvictionNotifierRunnable> r = new EvictionNotifierRunnable();
      NS_DispatchToMainThread(r);
    }
    return NS_ERROR_FILE_INVALID_PATH;
  }

  if (mShuttingDown) {
    return NS_ERROR_NOT_INITIALIZED;
  }

  if (!mTreeCreated) {
    rv = CreateCacheTree();
    if (NS_FAILED(rv)) {
      return rv;
    }
  }

  // Doom all active handles that matches the load context
  nsTArray<RefPtr<CacheFileHandle> > handles;
  mHandles.GetActiveHandles(&handles);

  for (uint32_t i = 0; i < handles.Length(); ++i) {
    CacheFileHandle* handle = handles[i];

    if (aLoadContextInfo) {
      bool equals;
      rv = CacheFileUtils::KeyMatchesLoadContextInfo(handle->Key(),
                                                     aLoadContextInfo,
                                                     &equals);
      if (NS_FAILED(rv)) {
        LOG(("CacheFileIOManager::EvictByContextInternal() - Cannot parse key in "
             "handle! [handle=%p, key=%s]", handle, handle->Key().get()));
        MOZ_CRASH("Unexpected error!");
      }

      if (!equals) {
        continue;
      }
    }

    // handle will be doomed only when pinning status is known and equal or
    // doom decision will be deferred until pinning status is determined.
    rv = DoomFileInternal(handle, aPinned
                                  ? CacheFileIOManager::DOOM_WHEN_PINNED
                                  : CacheFileIOManager::DOOM_WHEN_NON_PINNED);
    if (NS_WARN_IF(NS_FAILED(rv))) {
      LOG(("CacheFileIOManager::EvictByContextInternal() - Cannot doom handle"
            " [handle=%p]", handle));
    }
  }

  if (!aLoadContextInfo) {
    RefPtr<EvictionNotifierRunnable> r = new EvictionNotifierRunnable();
    NS_DispatchToMainThread(r);
  }

  if (!mContextEvictor) {
    mContextEvictor = new CacheFileContextEvictor();
    mContextEvictor->Init(mCacheDirectory);
  }

  mContextEvictor->AddContext(aLoadContextInfo, aPinned);

  return NS_OK;
}

// static
nsresult
CacheFileIOManager::CacheIndexStateChanged()
{
  LOG(("CacheFileIOManager::CacheIndexStateChanged()"));

  nsresult rv;

  // CacheFileIOManager lives longer than CacheIndex so gInstance must be
  // non-null here.
  MOZ_ASSERT(gInstance);

  // We have to re-distatch even if we are on IO thread to prevent reentering
  // the lock in CacheIndex
  nsCOMPtr<nsIRunnable> ev;
  ev = NewRunnableMethod(
    gInstance.get(), &CacheFileIOManager::CacheIndexStateChangedInternal);

  nsCOMPtr<nsIEventTarget> ioTarget = IOTarget();
  MOZ_ASSERT(ioTarget);

  rv = ioTarget->Dispatch(ev, nsIEventTarget::DISPATCH_NORMAL);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  return NS_OK;
}

nsresult
CacheFileIOManager::CacheIndexStateChangedInternal()
{
  if (mShuttingDown) {
    // ignore notification during shutdown
    return NS_OK;
  }

  if (!mContextEvictor) {
    return NS_OK;
  }

  mContextEvictor->CacheIndexStateChanged();
  return NS_OK;
}

nsresult
CacheFileIOManager::TrashDirectory(nsIFile *aFile)
{
  nsAutoCString path;
  aFile->GetNativePath(path);
  LOG(("CacheFileIOManager::TrashDirectory() [file=%s]", path.get()));

  nsresult rv;

  MOZ_ASSERT(mIOThread->IsCurrentThread());
  MOZ_ASSERT(mCacheDirectory);

  // When the directory is empty, it is cheaper to remove it directly instead of
  // using the trash mechanism.
  bool isEmpty;
  rv = IsEmptyDirectory(aFile, &isEmpty);
  NS_ENSURE_SUCCESS(rv, rv);

  if (isEmpty) {
    rv = aFile->Remove(false);
    LOG(("CacheFileIOManager::TrashDirectory() - Directory removed [rv=0x%08x]",
         rv));
    return rv;
  }

#ifdef DEBUG
  nsCOMPtr<nsIFile> dirCheck;
  rv = aFile->GetParent(getter_AddRefs(dirCheck));
  NS_ENSURE_SUCCESS(rv, rv);

  bool equals = false;
  rv = dirCheck->Equals(mCacheDirectory, &equals);
  NS_ENSURE_SUCCESS(rv, rv);

  MOZ_ASSERT(equals);
#endif

  nsCOMPtr<nsIFile> dir, trash;
  nsAutoCString leaf;

  rv = aFile->Clone(getter_AddRefs(dir));
  NS_ENSURE_SUCCESS(rv, rv);

  rv = aFile->Clone(getter_AddRefs(trash));
  NS_ENSURE_SUCCESS(rv, rv);

  const int32_t kMaxTries = 16;
  srand(static_cast<unsigned>(PR_Now()));
  for (int32_t triesCount = 0; ; ++triesCount) {
    leaf = TRASH_DIR;
    leaf.AppendInt(rand());
    rv = trash->SetNativeLeafName(leaf);
    NS_ENSURE_SUCCESS(rv, rv);

    bool exists;
    if (NS_SUCCEEDED(trash->Exists(&exists)) && !exists) {
      break;
    }

    LOG(("CacheFileIOManager::TrashDirectory() - Trash directory already "
         "exists [leaf=%s]", leaf.get()));

    if (triesCount == kMaxTries) {
      LOG(("CacheFileIOManager::TrashDirectory() - Could not find unused trash "
           "directory in %d tries.", kMaxTries));
      return NS_ERROR_FAILURE;
    }
  }

  LOG(("CacheFileIOManager::TrashDirectory() - Renaming directory [leaf=%s]",
       leaf.get()));

  rv = dir->MoveToNative(nullptr, leaf);
  NS_ENSURE_SUCCESS(rv, rv);

  StartRemovingTrash();
  return NS_OK;
}

// static
void
CacheFileIOManager::OnTrashTimer(nsITimer *aTimer, void *aClosure)
{
  LOG(("CacheFileIOManager::OnTrashTimer() [timer=%p, closure=%p]", aTimer,
       aClosure));

  RefPtr<CacheFileIOManager> ioMan = gInstance;

  if (!ioMan) {
    return;
  }

  ioMan->mTrashTimer = nullptr;
  ioMan->StartRemovingTrash();
}

nsresult
CacheFileIOManager::StartRemovingTrash()
{
  LOG(("CacheFileIOManager::StartRemovingTrash()"));

  nsresult rv;

  MOZ_ASSERT(mIOThread->IsCurrentThread());

  if (mShuttingDown) {
    return NS_ERROR_NOT_INITIALIZED;
  }

  if (!mCacheDirectory) {
    return NS_ERROR_FILE_INVALID_PATH;
  }

  if (mTrashTimer) {
    LOG(("CacheFileIOManager::StartRemovingTrash() - Trash timer exists."));
    return NS_OK;
  }

  if (mRemovingTrashDirs) {
    LOG(("CacheFileIOManager::StartRemovingTrash() - Trash removing in "
         "progress."));
    return NS_OK;
  }

  uint32_t elapsed = (TimeStamp::NowLoRes() - mStartTime).ToMilliseconds();
  if (elapsed < kRemoveTrashStartDelay) {
    nsCOMPtr<nsITimer> timer = do_CreateInstance("@mozilla.org/timer;1", &rv);
    NS_ENSURE_SUCCESS(rv, rv);

    nsCOMPtr<nsIEventTarget> ioTarget = IOTarget();
    MOZ_ASSERT(ioTarget);

    rv = timer->SetTarget(ioTarget);
    NS_ENSURE_SUCCESS(rv, rv);

    rv = timer->InitWithFuncCallback(CacheFileIOManager::OnTrashTimer, nullptr,
                                     kRemoveTrashStartDelay - elapsed,
                                     nsITimer::TYPE_ONE_SHOT);
    NS_ENSURE_SUCCESS(rv, rv);

    mTrashTimer.swap(timer);
    return NS_OK;
  }

  nsCOMPtr<nsIRunnable> ev;
  ev = NewRunnableMethod(this,
			 &CacheFileIOManager::RemoveTrashInternal);

  rv = mIOThread->Dispatch(ev, CacheIOThread::EVICT);
  NS_ENSURE_SUCCESS(rv, rv);

  mRemovingTrashDirs = true;
  return NS_OK;
}

nsresult
CacheFileIOManager::RemoveTrashInternal()
{
  LOG(("CacheFileIOManager::RemoveTrashInternal()"));

  nsresult rv;

  MOZ_ASSERT(mIOThread->IsCurrentThread());

  if (mShuttingDown) {
    return NS_ERROR_NOT_INITIALIZED;
  }

  CacheIOThread::Cancelable cancelable(true);

  MOZ_ASSERT(!mTrashTimer);
  MOZ_ASSERT(mRemovingTrashDirs);

  if (!mTreeCreated) {
    rv = CreateCacheTree();
    if (NS_FAILED(rv)) {
      return rv;
    }
  }

  // mRemovingTrashDirs is accessed only on IO thread, so we can drop the flag
  // here and set it again once we dispatch a continuation event. By doing so,
  // we don't have to drop the flag on any possible early return.
  mRemovingTrashDirs = false;

  while (true) {
    if (CacheIOThread::YieldAndRerun()) {
      LOG(("CacheFileIOManager::RemoveTrashInternal() - Breaking loop for "
           "higher level events."));
      mRemovingTrashDirs = true;
      return NS_OK;
    }

    // Find some trash directory
    if (!mTrashDir) {
      MOZ_ASSERT(!mTrashDirEnumerator);

      rv = FindTrashDirToRemove();
      if (rv == NS_ERROR_NOT_AVAILABLE) {
        LOG(("CacheFileIOManager::RemoveTrashInternal() - No trash directory "
             "found."));
        return NS_OK;
      }
      NS_ENSURE_SUCCESS(rv, rv);

      nsCOMPtr<nsISimpleEnumerator> enumerator;
      rv = mTrashDir->GetDirectoryEntries(getter_AddRefs(enumerator));
      if (NS_SUCCEEDED(rv)) {
        mTrashDirEnumerator = do_QueryInterface(enumerator, &rv);
        NS_ENSURE_SUCCESS(rv, rv);
      }

      continue; // check elapsed time
    }

    // We null out mTrashDirEnumerator once we remove all files in the
    // directory, so remove the trash directory if we don't have enumerator.
    if (!mTrashDirEnumerator) {
      rv = mTrashDir->Remove(false);
      if (NS_FAILED(rv)) {
        // There is no reason why removing an empty directory should fail, but
        // if it does, we should continue and try to remove all other trash
        // directories.
        nsAutoCString leafName;
        mTrashDir->GetNativeLeafName(leafName);
        mFailedTrashDirs.AppendElement(leafName);
        LOG(("CacheFileIOManager::RemoveTrashInternal() - Cannot remove "
             "trashdir. [name=%s]", leafName.get()));
      }

      mTrashDir = nullptr;
      continue; // check elapsed time
    }

    nsCOMPtr<nsIFile> file;
    rv = mTrashDirEnumerator->GetNextFile(getter_AddRefs(file));
    if (!file) {
      mTrashDirEnumerator->Close();
      mTrashDirEnumerator = nullptr;
      continue; // check elapsed time
    } else {
      bool isDir = false;
      file->IsDirectory(&isDir);
      if (isDir) {
        NS_WARNING("Found a directory in a trash directory! It will be removed "
                   "recursively, but this can block IO thread for a while!");
        if (LOG_ENABLED()) {
          nsAutoCString path;
          file->GetNativePath(path);
          LOG(("CacheFileIOManager::RemoveTrashInternal() - Found a directory in a trash "
              "directory! It will be removed recursively, but this can block IO "
              "thread for a while! [file=%s]", path.get()));
        }
      }
      file->Remove(isDir);
    }
  }

  NS_NOTREACHED("We should never get here");
  return NS_OK;
}

nsresult
CacheFileIOManager::FindTrashDirToRemove()
{
  LOG(("CacheFileIOManager::FindTrashDirToRemove()"));

  nsresult rv;

  // We call this method on the main thread during shutdown when user wants to
  // remove all cache files.
  MOZ_ASSERT(mIOThread->IsCurrentThread() || mShuttingDown);

  nsCOMPtr<nsISimpleEnumerator> iter;
  rv = mCacheDirectory->GetDirectoryEntries(getter_AddRefs(iter));
  NS_ENSURE_SUCCESS(rv, rv);

  bool more;
  nsCOMPtr<nsISupports> elem;

  while (NS_SUCCEEDED(iter->HasMoreElements(&more)) && more) {
    rv = iter->GetNext(getter_AddRefs(elem));
    if (NS_FAILED(rv)) {
      continue;
    }

    nsCOMPtr<nsIFile> file = do_QueryInterface(elem);
    if (!file) {
      continue;
    }

    bool isDir = false;
    file->IsDirectory(&isDir);
    if (!isDir) {
      continue;
    }

    nsAutoCString leafName;
    rv = file->GetNativeLeafName(leafName);
    if (NS_FAILED(rv)) {
      continue;
    }

    if (leafName.Length() < strlen(TRASH_DIR)) {
      continue;
    }

    if (!StringBeginsWith(leafName, NS_LITERAL_CSTRING(TRASH_DIR))) {
      continue;
    }

    if (mFailedTrashDirs.Contains(leafName)) {
      continue;
    }

    LOG(("CacheFileIOManager::FindTrashDirToRemove() - Returning directory %s",
         leafName.get()));

    mTrashDir = file;
    return NS_OK;
  }

  // When we're here we've tried to delete all trash directories. Clear
  // mFailedTrashDirs so we will try to delete them again when we start removing
  // trash directories next time.
  mFailedTrashDirs.Clear();
  return NS_ERROR_NOT_AVAILABLE;
}

// static
nsresult
CacheFileIOManager::InitIndexEntry(CacheFileHandle *aHandle,
                                   OriginAttrsHash  aOriginAttrsHash,
                                   bool             aAnonymous,
                                   bool             aPinning)
{
  LOG(("CacheFileIOManager::InitIndexEntry() [handle=%p, originAttrsHash=%llx, "
       "anonymous=%d, pinning=%d]", aHandle, aOriginAttrsHash, aAnonymous,
       aPinning));

  nsresult rv;
  RefPtr<CacheFileIOManager> ioMan = gInstance;

  if (aHandle->IsClosed() || !ioMan) {
    return NS_ERROR_NOT_INITIALIZED;
  }

  if (aHandle->IsSpecialFile()) {
    return NS_ERROR_UNEXPECTED;
  }

  RefPtr<InitIndexEntryEvent> ev =
    new InitIndexEntryEvent(aHandle, aOriginAttrsHash, aAnonymous, aPinning);
  rv = ioMan->mIOThread->Dispatch(ev, aHandle->mPriority
                                  ? CacheIOThread::WRITE_PRIORITY
                                  : CacheIOThread::WRITE);
  NS_ENSURE_SUCCESS(rv, rv);

  return NS_OK;
}

// static
nsresult
CacheFileIOManager::UpdateIndexEntry(CacheFileHandle *aHandle,
                                     const uint32_t  *aFrecency,
                                     const uint32_t  *aExpirationTime)
{
  LOG(("CacheFileIOManager::UpdateIndexEntry() [handle=%p, frecency=%s, "
       "expirationTime=%s]", aHandle,
       aFrecency ? nsPrintfCString("%u", *aFrecency).get() : "",
       aExpirationTime ? nsPrintfCString("%u", *aExpirationTime).get() : ""));

  nsresult rv;
  RefPtr<CacheFileIOManager> ioMan = gInstance;

  if (aHandle->IsClosed() || !ioMan) {
    return NS_ERROR_NOT_INITIALIZED;
  }

  if (aHandle->IsSpecialFile()) {
    return NS_ERROR_UNEXPECTED;
  }

  RefPtr<UpdateIndexEntryEvent> ev =
    new UpdateIndexEntryEvent(aHandle, aFrecency, aExpirationTime);
  rv = ioMan->mIOThread->Dispatch(ev, aHandle->mPriority
                                  ? CacheIOThread::WRITE_PRIORITY
                                  : CacheIOThread::WRITE);
  NS_ENSURE_SUCCESS(rv, rv);

  return NS_OK;
}

nsresult
CacheFileIOManager::CreateFile(CacheFileHandle *aHandle)
{
  MOZ_ASSERT(!aHandle->mFD);
  MOZ_ASSERT(aHandle->mFile);

  nsresult rv;

  if (aHandle->IsDoomed()) {
    nsCOMPtr<nsIFile> file;

    rv = GetDoomedFile(getter_AddRefs(file));
    NS_ENSURE_SUCCESS(rv, rv);

    aHandle->mFile.swap(file);
  } else {
    bool exists;
    if (NS_SUCCEEDED(aHandle->mFile->Exists(&exists)) && exists) {
      NS_WARNING("Found a file that should not exist!");
    }
  }

  rv = OpenNSPRHandle(aHandle, true);
  NS_ENSURE_SUCCESS(rv, rv);

  aHandle->mFileSize = 0;
  return NS_OK;
}

// static
void
CacheFileIOManager::HashToStr(const SHA1Sum::Hash *aHash, nsACString &_retval)
{
  _retval.Truncate();
  const char hexChars[] = {'0', '1', '2', '3', '4', '5', '6', '7',
                           '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
  for (uint32_t i=0 ; i<sizeof(SHA1Sum::Hash) ; i++) {
    _retval.Append(hexChars[(*aHash)[i] >> 4]);
    _retval.Append(hexChars[(*aHash)[i] & 0xF]);
  }
}

// static
nsresult
CacheFileIOManager::StrToHash(const nsACString &aHash, SHA1Sum::Hash *_retval)
{
  if (aHash.Length() != 2*sizeof(SHA1Sum::Hash)) {
    return NS_ERROR_INVALID_ARG;
  }

  for (uint32_t i=0 ; i<aHash.Length() ; i++) {
    uint8_t value;

    if (aHash[i] >= '0' && aHash[i] <= '9') {
      value = aHash[i] - '0';
    } else if (aHash[i] >= 'A' && aHash[i] <= 'F') {
      value = aHash[i] - 'A' + 10;
    } else if (aHash[i] >= 'a' && aHash[i] <= 'f') {
      value = aHash[i] - 'a' + 10;
    } else {
      return NS_ERROR_INVALID_ARG;
    }

    if (i%2 == 0) {
      (reinterpret_cast<uint8_t *>(_retval))[i/2] = value << 4;
    } else {
      (reinterpret_cast<uint8_t *>(_retval))[i/2] += value;
    }
  }

  return NS_OK;
}

nsresult
CacheFileIOManager::GetFile(const SHA1Sum::Hash *aHash, nsIFile **_retval)
{
  nsresult rv;
  nsCOMPtr<nsIFile> file;
  rv = mCacheDirectory->Clone(getter_AddRefs(file));
  NS_ENSURE_SUCCESS(rv, rv);

  rv = file->AppendNative(NS_LITERAL_CSTRING(ENTRIES_DIR));
  NS_ENSURE_SUCCESS(rv, rv);

  nsAutoCString leafName;
  HashToStr(aHash, leafName);

  rv = file->AppendNative(leafName);
  NS_ENSURE_SUCCESS(rv, rv);

  file.swap(*_retval);
  return NS_OK;
}

nsresult
CacheFileIOManager::GetSpecialFile(const nsACString &aKey, nsIFile **_retval)
{
  nsresult rv;
  nsCOMPtr<nsIFile> file;
  rv = mCacheDirectory->Clone(getter_AddRefs(file));
  NS_ENSURE_SUCCESS(rv, rv);

  rv = file->AppendNative(aKey);
  NS_ENSURE_SUCCESS(rv, rv);

  file.swap(*_retval);
  return NS_OK;
}

nsresult
CacheFileIOManager::GetDoomedFile(nsIFile **_retval)
{
  nsresult rv;
  nsCOMPtr<nsIFile> file;
  rv = mCacheDirectory->Clone(getter_AddRefs(file));
  NS_ENSURE_SUCCESS(rv, rv);

  rv = file->AppendNative(NS_LITERAL_CSTRING(DOOMED_DIR));
  NS_ENSURE_SUCCESS(rv, rv);

  rv = file->AppendNative(NS_LITERAL_CSTRING("dummyleaf"));
  NS_ENSURE_SUCCESS(rv, rv);

  const int32_t kMaxTries = 64;
  srand(static_cast<unsigned>(PR_Now()));
  nsAutoCString leafName;
  for (int32_t triesCount = 0; ; ++triesCount) {
    leafName.AppendInt(rand());
    rv = file->SetNativeLeafName(leafName);
    NS_ENSURE_SUCCESS(rv, rv);

    bool exists;
    if (NS_SUCCEEDED(file->Exists(&exists)) && !exists) {
      break;
    }

    if (triesCount == kMaxTries) {
      LOG(("CacheFileIOManager::GetDoomedFile() - Could not find unused file "
           "name in %d tries.", kMaxTries));
      return NS_ERROR_FAILURE;
    }

    leafName.Truncate();
  }

  file.swap(*_retval);
  return NS_OK;
}

nsresult
CacheFileIOManager::IsEmptyDirectory(nsIFile *aFile, bool *_retval)
{
  MOZ_ASSERT(mIOThread->IsCurrentThread());

  nsresult rv;

  nsCOMPtr<nsISimpleEnumerator> enumerator;
  rv = aFile->GetDirectoryEntries(getter_AddRefs(enumerator));
  NS_ENSURE_SUCCESS(rv, rv);

  bool hasMoreElements = false;
  rv = enumerator->HasMoreElements(&hasMoreElements);
  NS_ENSURE_SUCCESS(rv, rv);

  *_retval = !hasMoreElements;
  return NS_OK;
}

nsresult
CacheFileIOManager::CheckAndCreateDir(nsIFile *aFile, const char *aDir,
                                      bool aEnsureEmptyDir)
{
  nsresult rv;

  nsCOMPtr<nsIFile> file;
  if (!aDir) {
    file = aFile;
  } else {
    nsAutoCString dir(aDir);
    rv = aFile->Clone(getter_AddRefs(file));
    NS_ENSURE_SUCCESS(rv, rv);
    rv = file->AppendNative(dir);
    NS_ENSURE_SUCCESS(rv, rv);
  }

  bool exists = false;
  rv = file->Exists(&exists);
  if (NS_SUCCEEDED(rv) && exists) {
    bool isDirectory = false;
    rv = file->IsDirectory(&isDirectory);
    if (NS_FAILED(rv) || !isDirectory) {
      // Try to remove the file
      rv = file->Remove(false);
      if (NS_SUCCEEDED(rv)) {
        exists = false;
      }
    }
    NS_ENSURE_SUCCESS(rv, rv);
  }

  if (aEnsureEmptyDir && NS_SUCCEEDED(rv) && exists) {
    bool isEmpty;
    rv = IsEmptyDirectory(file, &isEmpty);
    NS_ENSURE_SUCCESS(rv, rv);

    if (!isEmpty) {
      // Don't check the result, if this fails, it's OK.  We do this
      // only for the doomed directory that doesn't need to be deleted
      // for the cost of completely disabling the whole browser.
      TrashDirectory(file);
    }
  }

  if (NS_SUCCEEDED(rv) && !exists) {
    rv = file->Create(nsIFile::DIRECTORY_TYPE, 0700);
  }
  if (NS_FAILED(rv)) {
    NS_WARNING("Cannot create directory");
    return NS_ERROR_FAILURE;
  }

  return NS_OK;
}

nsresult
CacheFileIOManager::CreateCacheTree()
{
  MOZ_ASSERT(mIOThread->IsCurrentThread());
  MOZ_ASSERT(!mTreeCreated);

  if (!mCacheDirectory || mTreeCreationFailed) {
    return NS_ERROR_FILE_INVALID_PATH;
  }

  nsresult rv;

  // Set the flag here and clear it again below when the tree is created
  // successfully.
  mTreeCreationFailed = true;

  // ensure parent directory exists
  nsCOMPtr<nsIFile> parentDir;
  rv = mCacheDirectory->GetParent(getter_AddRefs(parentDir));
  NS_ENSURE_SUCCESS(rv, rv);
  rv = CheckAndCreateDir(parentDir, nullptr, false);
  NS_ENSURE_SUCCESS(rv, rv);

  // ensure cache directory exists
  rv = CheckAndCreateDir(mCacheDirectory, nullptr, false);
  NS_ENSURE_SUCCESS(rv, rv);

  // ensure entries directory exists
  rv = CheckAndCreateDir(mCacheDirectory, ENTRIES_DIR, false);
  NS_ENSURE_SUCCESS(rv, rv);

  // ensure doomed directory exists
  rv = CheckAndCreateDir(mCacheDirectory, DOOMED_DIR, true);
  NS_ENSURE_SUCCESS(rv, rv);

  mTreeCreated = true;
  mTreeCreationFailed = false;

  if (!mContextEvictor) {
    RefPtr<CacheFileContextEvictor> contextEvictor;
    contextEvictor = new CacheFileContextEvictor();

    // Init() method will try to load unfinished contexts from the disk. Store
    // the evictor as a member only when there is some unfinished job.
    contextEvictor->Init(mCacheDirectory);
    if (contextEvictor->ContextsCount()) {
      contextEvictor.swap(mContextEvictor);
    }
  }

  StartRemovingTrash();

  return NS_OK;
}

nsresult
CacheFileIOManager::OpenNSPRHandle(CacheFileHandle *aHandle, bool aCreate)
{
  LOG(("CacheFileIOManager::OpenNSPRHandle BEGIN, handle=%p", aHandle));

  MOZ_ASSERT(CacheFileIOManager::IsOnIOThreadOrCeased());
  MOZ_ASSERT(!aHandle->mFD);
  MOZ_ASSERT(mHandlesByLastUsed.IndexOf(aHandle) == mHandlesByLastUsed.NoIndex);
  MOZ_ASSERT(mHandlesByLastUsed.Length() <= kOpenHandlesLimit);
  MOZ_ASSERT((aCreate && !aHandle->mFileExists) ||
             (!aCreate && aHandle->mFileExists));

  nsresult rv;

  if (mHandlesByLastUsed.Length() == kOpenHandlesLimit) {
    // close handle that hasn't been used for the longest time
    rv = MaybeReleaseNSPRHandleInternal(mHandlesByLastUsed[0], true);
    NS_ENSURE_SUCCESS(rv, rv);
  }

  if (aCreate) {
    rv = aHandle->mFile->OpenNSPRFileDesc(
           PR_RDWR | PR_CREATE_FILE | PR_TRUNCATE, 0600, &aHandle->mFD);
    if (rv == NS_ERROR_FILE_ALREADY_EXISTS ||  // error from nsLocalFileWin
        rv == NS_ERROR_FILE_NO_DEVICE_SPACE) { // error from nsLocalFileUnix
      LOG(("CacheFileIOManager::OpenNSPRHandle() - Cannot create a new file, we"
           " might reached a limit on FAT32. Will evict a single entry and try "
           "again. [hash=%08x%08x%08x%08x%08x]", LOGSHA1(aHandle->Hash())));

      SHA1Sum::Hash hash;
      uint32_t cnt;

      rv = CacheIndex::GetEntryForEviction(true, &hash, &cnt);
      if (NS_SUCCEEDED(rv)) {
        rv = DoomFileByKeyInternal(&hash);
      }
      if (NS_SUCCEEDED(rv)) {
        rv = aHandle->mFile->OpenNSPRFileDesc(
               PR_RDWR | PR_CREATE_FILE | PR_TRUNCATE, 0600, &aHandle->mFD);
        LOG(("CacheFileIOManager::OpenNSPRHandle() - Successfully evicted entry"
             " with hash %08x%08x%08x%08x%08x. %s to create the new file.",
             LOGSHA1(&hash), NS_SUCCEEDED(rv) ? "Succeeded" : "Failed"));
      } else {
        LOG(("CacheFileIOManager::OpenNSPRHandle() - Couldn't evict an existing"
             " entry."));
        rv = NS_ERROR_FILE_NO_DEVICE_SPACE;
      }
    }
    if (NS_FAILED(rv)) {
      LOG(("CacheFileIOManager::OpenNSPRHandle() Create failed with 0x%08x", rv));
    }
    NS_ENSURE_SUCCESS(rv, rv);

    aHandle->mFileExists = true;
  } else {
    rv = aHandle->mFile->OpenNSPRFileDesc(PR_RDWR, 0600, &aHandle->mFD);
    if (NS_ERROR_FILE_NOT_FOUND == rv) {
      LOG(("  file doesn't exists"));
      aHandle->mFileExists = false;
      return DoomFileInternal(aHandle);
    }
    if (NS_FAILED(rv)) {
      LOG(("CacheFileIOManager::OpenNSPRHandle() Open failed with 0x%08x", rv));
    }
    NS_ENSURE_SUCCESS(rv, rv);
  }

  mHandlesByLastUsed.AppendElement(aHandle);

  LOG(("CacheFileIOManager::OpenNSPRHandle END, handle=%p", aHandle));

  return NS_OK;
}

void
CacheFileIOManager::NSPRHandleUsed(CacheFileHandle *aHandle)
{
  MOZ_ASSERT(CacheFileIOManager::IsOnIOThreadOrCeased());
  MOZ_ASSERT(aHandle->mFD);

  DebugOnly<bool> found;
  found = mHandlesByLastUsed.RemoveElement(aHandle);
  MOZ_ASSERT(found);

  mHandlesByLastUsed.AppendElement(aHandle);
}

nsresult
CacheFileIOManager::SyncRemoveDir(nsIFile *aFile, const char *aDir)
{
  nsresult rv;
  nsCOMPtr<nsIFile> file;

  if (!aDir) {
    file = aFile;
  } else {
    rv = aFile->Clone(getter_AddRefs(file));
    if (NS_WARN_IF(NS_FAILED(rv))) {
      return rv;
    }

    rv = file->AppendNative(nsDependentCString(aDir));
    if (NS_WARN_IF(NS_FAILED(rv))) {
      return rv;
    }
  }

  if (LOG_ENABLED()) {
    nsAutoCString path;
    file->GetNativePath(path);
    LOG(("CacheFileIOManager::SyncRemoveDir() - Removing directory %s",
         path.get()));
  }

  rv = file->Remove(true);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    LOG(("CacheFileIOManager::SyncRemoveDir() - Removing failed! [rv=0x%08x]",
         rv));
  }

  return rv;
}

void
CacheFileIOManager::SyncRemoveAllCacheFiles()
{
  LOG(("CacheFileIOManager::SyncRemoveAllCacheFiles()"));

  nsresult rv;

  SyncRemoveDir(mCacheDirectory, ENTRIES_DIR);
  SyncRemoveDir(mCacheDirectory, DOOMED_DIR);

  // Clear any intermediate state of trash dir enumeration.
  mFailedTrashDirs.Clear();
  mTrashDir = nullptr;

  while (true) {
    // FindTrashDirToRemove() fills mTrashDir if there is any trash directory.
    rv = FindTrashDirToRemove();
    if (rv == NS_ERROR_NOT_AVAILABLE) {
      LOG(("CacheFileIOManager::SyncRemoveAllCacheFiles() - No trash directory "
           "found."));
      break;
    }
    if (NS_WARN_IF(NS_FAILED(rv))) {
      LOG(("CacheFileIOManager::SyncRemoveAllCacheFiles() - "
           "FindTrashDirToRemove() returned an unexpected error. [rv=0x%08x]",
           rv));
      break;
    }

    rv = SyncRemoveDir(mTrashDir, nullptr);
    if (NS_FAILED(rv)) {
      nsAutoCString leafName;
      mTrashDir->GetNativeLeafName(leafName);
      mFailedTrashDirs.AppendElement(leafName);
    }
  }
}

// Returns default ("smart") size (in KB) of cache, given available disk space
// (also in KB)
static uint32_t
SmartCacheSize(const uint32_t availKB)
{
  uint32_t maxSize = kMaxCacheSizeKB;

  if (availKB > 100 * 1024 * 1024) {
    return maxSize;  // skip computing if we're over 100 GB
  }

  // Grow/shrink in 10 MB units, deliberately, so that in the common case we
  // don't shrink cache and evict items every time we startup (it's important
  // that we don't slow down startup benchmarks).
  uint32_t sz10MBs = 0;
  uint32_t avail10MBs = availKB / (1024*10);

  // .5% of space above 25 GB
  if (avail10MBs > 2500) {
    sz10MBs += static_cast<uint32_t>((avail10MBs - 2500)*.005);
    avail10MBs = 2500;
  }
  // 1% of space between 7GB -> 25 GB
  if (avail10MBs > 700) {
    sz10MBs += static_cast<uint32_t>((avail10MBs - 700)*.01);
    avail10MBs = 700;
  }
  // 5% of space between 500 MB -> 7 GB
  if (avail10MBs > 50) {
    sz10MBs += static_cast<uint32_t>((avail10MBs - 50)*.05);
    avail10MBs = 50;
  }

  // 40% of space up to 500 MB (50 MB min)
  sz10MBs += std::max<uint32_t>(5, static_cast<uint32_t>(avail10MBs * .4));

  return std::min<uint32_t>(maxSize, sz10MBs * 10 * 1024);
}

nsresult
CacheFileIOManager::UpdateSmartCacheSize(int64_t aFreeSpace)
{
  MOZ_ASSERT(mIOThread->IsCurrentThread());

  nsresult rv;

  if (!CacheObserver::UseNewCache()) {
    return NS_ERROR_NOT_AVAILABLE;
  }

  if (!CacheObserver::SmartCacheSizeEnabled()) {
    return NS_ERROR_NOT_AVAILABLE;
  }

  // Wait at least kSmartSizeUpdateInterval before recomputing smart size.
  static const TimeDuration kUpdateLimit =
    TimeDuration::FromMilliseconds(kSmartSizeUpdateInterval);
  if (!mLastSmartSizeTime.IsNull() &&
      (TimeStamp::NowLoRes() - mLastSmartSizeTime) < kUpdateLimit) {
    return NS_OK;
  }

  // Do not compute smart size when cache size is not reliable.
  bool isUpToDate = false;
  CacheIndex::IsUpToDate(&isUpToDate);
  if (!isUpToDate) {
    return NS_ERROR_NOT_AVAILABLE;
  }

  uint32_t cacheUsage;
  rv = CacheIndex::GetCacheSize(&cacheUsage);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    LOG(("CacheFileIOManager::UpdateSmartCacheSize() - Cannot get cacheUsage! "
         "[rv=0x%08x]", rv));
    return rv;
  }

  mLastSmartSizeTime = TimeStamp::NowLoRes();

  uint32_t smartSize = SmartCacheSize(static_cast<uint32_t>(aFreeSpace / 1024) +
                                      cacheUsage);

  if (smartSize == (CacheObserver::DiskCacheCapacity() >> 10)) {
    // Smart size has not changed.
    return NS_OK;
  }

  CacheObserver::SetDiskCacheCapacity(smartSize << 10);

  return NS_OK;
}

// Memory reporting

namespace {

// A helper class that dispatches and waits for an event that gets result of
// CacheFileIOManager->mHandles.SizeOfExcludingThis() on the I/O thread
// to safely get handles memory report.
// We must do this, since the handle list is only accessed and managed w/o
// locking on the I/O thread.  That is by design.
class SizeOfHandlesRunnable : public Runnable
{
public:
  SizeOfHandlesRunnable(mozilla::MallocSizeOf mallocSizeOf,
                        CacheFileHandles const &handles,
                        nsTArray<CacheFileHandle *> const &specialHandles)
    : mMonitor("SizeOfHandlesRunnable.mMonitor")
    , mMallocSizeOf(mallocSizeOf)
    , mHandles(handles)
    , mSpecialHandles(specialHandles)
  {
  }

  size_t Get(CacheIOThread* thread)
  {
    nsCOMPtr<nsIEventTarget> target = thread->Target();
    if (!target) {
      NS_ERROR("If we have the I/O thread we also must have the I/O target");
      return 0;
    }

    mozilla::MonitorAutoLock mon(mMonitor);
    mMonitorNotified = false;
    nsresult rv = target->Dispatch(this, nsIEventTarget::DISPATCH_NORMAL);
    if (NS_FAILED(rv)) {
      NS_ERROR("Dispatch failed, cannot do memory report of CacheFileHandles");
      return 0;
    }

    while (!mMonitorNotified) {
      mon.Wait();
    }
    return mSize;
  }

  NS_IMETHOD Run() override
  {
    mozilla::MonitorAutoLock mon(mMonitor);
    // Excluding this since the object itself is a member of CacheFileIOManager
    // reported in CacheFileIOManager::SizeOfIncludingThis as part of |this|.
    mSize = mHandles.SizeOfExcludingThis(mMallocSizeOf);
    for (uint32_t i = 0; i < mSpecialHandles.Length(); ++i) {
      mSize += mSpecialHandles[i]->SizeOfIncludingThis(mMallocSizeOf);
    }

    mMonitorNotified = true;
    mon.Notify();
    return NS_OK;
  }

private:
  mozilla::Monitor mMonitor;
  bool mMonitorNotified;
  mozilla::MallocSizeOf mMallocSizeOf;
  CacheFileHandles const &mHandles;
  nsTArray<CacheFileHandle *> const &mSpecialHandles;
  size_t mSize;
};

} // namespace

size_t
CacheFileIOManager::SizeOfExcludingThisInternal(mozilla::MallocSizeOf mallocSizeOf) const
{
  size_t n = 0;
  nsCOMPtr<nsISizeOf> sizeOf;

  if (mIOThread) {
    n += mIOThread->SizeOfIncludingThis(mallocSizeOf);

    // mHandles and mSpecialHandles must be accessed only on the I/O thread,
    // must sync dispatch.
    RefPtr<SizeOfHandlesRunnable> sizeOfHandlesRunnable =
      new SizeOfHandlesRunnable(mallocSizeOf, mHandles, mSpecialHandles);
    n += sizeOfHandlesRunnable->Get(mIOThread);
  }

  // mHandlesByLastUsed just refers handles reported by mHandles.

  sizeOf = do_QueryInterface(mCacheDirectory);
  if (sizeOf)
    n += sizeOf->SizeOfIncludingThis(mallocSizeOf);

  sizeOf = do_QueryInterface(mMetadataWritesTimer);
  if (sizeOf)
    n += sizeOf->SizeOfIncludingThis(mallocSizeOf);

  sizeOf = do_QueryInterface(mTrashTimer);
  if (sizeOf)
    n += sizeOf->SizeOfIncludingThis(mallocSizeOf);

  sizeOf = do_QueryInterface(mTrashDir);
  if (sizeOf)
    n += sizeOf->SizeOfIncludingThis(mallocSizeOf);

  for (uint32_t i = 0; i < mFailedTrashDirs.Length(); ++i) {
    n += mFailedTrashDirs[i].SizeOfExcludingThisIfUnshared(mallocSizeOf);
  }

  return n;
}

// static
size_t
CacheFileIOManager::SizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf)
{
  if (!gInstance)
    return 0;

  return gInstance->SizeOfExcludingThisInternal(mallocSizeOf);
}

// static
size_t
CacheFileIOManager::SizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf)
{
  return mallocSizeOf(gInstance) + SizeOfExcludingThis(mallocSizeOf);
}

} // namespace net
} // namespace mozilla
